Any tips for heating/insulated bed with shell?

Hey there all!
Here's the deal.. I have a 2020 LB taco. Already have a Snugtop High Liner shell on it.
I plan on doing a lot of bucket-list camping this year. A lot of it in the South West. Think dessert.
These trips will be 1-2 months at a time between pit-stops at home base. Maybe more, who knows, I'm retired. I've got no where to go, and all day to get there.. LOL.
Anyway, knowing as hot as it gets in the dessert during the day, it gets butt-ass cold at night as well. Wanting to know who has done what to help insulate the back, because that's where I plan on sleeping.
I plan on getting a 3/8" thick Westin bed mat. Figure that's gotta help, plus helping to not kill my knees crawling in the back.I've also read about some fiberglass mats they say insulate well also.
For some heat (If needed) I'm running power (On it's own fused circuit, connected straight to the battery) line that will run under the the truck, attached to the frame, coming up through the drain hole in the front of the bed. That will be attached to a dual outlet, cigarette lighter style.
That allows me two things. 1.) To attach one of those 12v heaters, and 2.) to plug in a 180w inverter for running my laptop. (Already have a 1000w inverter mounted inside on the inside rear of the cab)..
The shell is, of course, fiberglass with some carpet-like stuff all on the inside. (Looks good actually... Snugtop did a good job on that)... Guessing there's not to much I can do to beef up that, but any tips would be appreciated.
Have two air mattresses, but those only last so long.... No matter how 'good/HD' they say they are. Want to get one of those nice thick pads, like the ones that they make for cots. Gotta be better than an air mattress. And I've got a decent sleeping bag, but it's only a summer bag. Plan on getting a 3-Season bag.
Anyway, anybody have some tips or better ideas for heating, or especially insulating?

 

Sounds like you are in for some great times. I too am retired and get out there camping/ fishing as often as I can.
A couple of things, first I really don’t think you are going to need heat in the back of your truck while sleeping. Yes it cools down at night in the desert but it doesn’t get that cold. I have a set up like yours and even in the winter when I go duck hunting and stay overnight I don’t use or need a heater. I assume you are going to be doing this spring, summer and early fall, no need for a heater. I have a LEER, no insulation just carpet. I think it would be really tough to adequately insulate the shell that it would do any good. The Westin bed mat is not comfortable to crawl around on. I do have a mat and carpet on top of it. Under the carpeting I have carpet padding, that insulates and makes it comfortable on my knees when I crawl around back there. I bought a piece of carpet and padding at Home Depot and cut them to fit the bed perfectly . Just get a good sleeping bag and you’ll be warm. Get a 3 or 4 season bag and get a large bag. Don’t get a mummy bag. They are restricting and uncomfortable and are really mainly for backpacking. Also don’t get down. Down is the best warmest insulation in the world but its main drawback is if it gets wet somehow it can take weeks to dry out and while wet it loses all its insulating properties. Do get a quality bag and not a Walmart special.

Everyone has their preferences for sleeping pads and there are thousands of them. Stay away from air mattresses, they will leak at some time and then you are screwed. What I use is a thick comfortable outdoor lounge pad and I have a piece of memory foam over the top of the pad. Comfortable as can be and I sleep soundly. It’s as comfortable as my tempur pedic foam bed at home. But you can look around there are lots of options.

I’ve been an outdoorsman my whole life (camping, backpacking, hunting , fishing etc etc) and can if you want provide a lot of info. And suggestions on things to bring along if you like.

 

Actually thinking about it a little more sleeping and hanging out in a the back of a small truck for a month or 2 at a time is not going to be comfortable or pleasant. If it were me I’d get a little tear drop trailer. Way more comfortable than the back of your truck, more roomy, it’s insulated and if you want you can easily heat it. Also going for 2 months at a time you are going to have to really load your truck up. Every day you’ll have to load and unload your truck just to have room to sleep. So it it works for you and you can afford the $$ check out a little tear drop. When you are done with it you can probably sell it for what you paid for it.

 

Or a pop up truck camper
Being unable to stand up inside shelter for months at a time sounds miserable

 

Thanks for the tips so far!
I probably should have prefaced this that I'm a camping vet. Have been so since about 10 years old... With parents and boy scouts, etc. I'm 68 now.
When I was married and the young-un's were young-un's I had a 3/4 ton Dodge conversion van and a 18' Komfort travel trailer. Many adventures! When the kids grew up and off to college, sold the trailer, pulled the rear seats out of the van and camped in that for a decade. Did several cross-country trips with the ex and then a buddy of mine. I know some awesome places to camp in Montana that the rest of the world has no idea about...
Anyway, don't want to pull any kind of trailer anymore. Nice to have but a PITA parking. I'd have to get a tow hitch for the truck, get a trailer... And I just don't want the hassle or spending $$ I don't really need to spend. Besides that, I've got the 2.7 4-banger, so not really a towing machine. And I like getting 25mpg.
I like the idea of the carpeting and padding. I will probably go bed-mat/padding/carpet. Sounds like good insulation and easy on the knees.
Upgrade the sleeping bag (No mummy bags! Had one once and hated it...) Extra long, because I like foot-space.
Still gonna run power to the bed, so still gonna get one of those 12v heaters. Granted, I just had a summer bag, but last year I drove to Houston for my best buddy's daughter's wedding. On the way home (WA.) stopped at a KOA in Seligam AZ. It was Sept. and in the 90's during the day. Night time though... woke up at 4AM freezing my ass off. So cold I couldn't sleep. I'm 68 and thin... I get cold! LOL!
Anyway I figure better to have it and not need it, than need it and not have it. And those little heaters are only $20-25.00, soooo....
I really don't mind being out/gone/camping for months at a time. My last cross-country trip was back east. I'm kinda' a Civil War geek, so spent 2 months visiting a couple dozen battle fields. Of course stayed at a motel every now and then (Shower and laundry) but I've never had a 'OK, enough of this' thought.
And I travel light. Very... If something has no real need or purpose, don't need it. No prob living off of 'poor college student' food. I'd probably do very well in Slab City.. LOL!

 

No bigger than the inside space is in a 4-1/2 x6 foot bed with a shell over it, your body heat will help warm it. I would make sure you have no places for breezes to penetrate, like around the tailgate and windows of the bed shell. You could insulate the sides of the bed and inside of the cap with pink foam and then line it for aesthetics. As for the bed floor, how much effort do you want to make to insulate it? Spray foam underneath might be an option, but IMO is a messy way. Easier would be a piece of thick carpet cut to fit the bed inside. An air mattress gives excellent insulation from the surface you're lying on, and a good quality one made of a sealed woven material will last a long time, just don't play with knives while you're in there, lol. I wrap mine in a furniture quilt to keep it from squeaking when I toss and turn, and I use a square bottomed (not a mummy) sleeping bag rated for about 20 degrees. I love camping but I'm 70 now and sleeping on the hard ground and getting wet doesn't appeal to me like it used to. The trailer is still bigger inside than a pickup bed with a cap, but not so big you want to stay in it when you get to the camp area. It gives a great dry and warm spot during bad weather. One thing I'd recommend related to power. is to have a separate battery to power your inverters, hooked into the system so it charges while you drive. Then you don't risk running down your truck battery and stranding yourself. I did that for the trailer I use (see below) and I can run my trailer lights inside, plus power my telescopes, etc. It looks like this (at bottom) and has a deep cycle marine battery:


I went a slightly different way, I bought a V-nosed 5x8 foot enclosed trailer, as my truck is a short bed and impossible to stretch out in the back. I put a crank-up roof vent in the trailer, it already had vents in the sides, and I insulated the walls and roof. The floor is 3/4" plywood and I did the spray foam underneath a patch at a time around the frame rails, and pushed cut-to-fit pink foam board 1" thick into the spaces between the square tube frame. Once that cured I did an undercoating with bedliner and it is undamaged after 7 years of use on the road and back country. I plan to add a couple of small side windows at some point, but I usually keep the back doors open (two that swing out, not a ramp door) and I have a curtain setup and mosquito screen for bugs and cold. I am an amateur astronomer and go to star parties and club nights for observing and astrophotography in dark areas, and haul all my equipment in the trailer or pickup bed, which I have a fold-up cover on. The trailer has a drop-down platform for a bed that allows storage underneath while it is down, and the front V-section has shelves that can be installed without tools and removed when I need the trailer for hauling stuff. The trailer weighs about 800 pounds, maybe 1100 with all the camping and astro gear aboard; the Taco doesn't even know it's back there. These are pics when I started working on the trailer, but you get the general idea of the layout. I've since made a frame that fits over the top of the doors when opened 90 degrees and a tarp fits over the frame between the doors, extending the covered area and giving me a dry place to sit outside if it rains, plus I can keep the doors open and keep it from raining in.

 

I gave up on air mattresses, just are never comfortable unless you sleep flat on your back and never move. The thick , self inflating Therma-rest pads are my choice. They roll up and stow away nicely.
I've been looking at low tec heated blankets. Made to run off 110V , but what happens at 12V? Just enough to keep off a chilly night? Plus, It's another blanket!

Your efforts are going to be rewarded. An open schedule in the American SW is an invitation to go lots of places slowly! Don't miss Mesa Verde !

 

I've spent a good bit of time sleeping in the back of my truck (and VW Westy when I had it; the VW was far more comfortable/practical in that regard)- buying a cab high shell for the current truck was one of my biggest mistakes. That out of the way, rambling, random thoughts time.

Do not build a platform if you plan to stay in it for more than a night or two; actually living out of the back you'll want as much room as possible to actually move around. For some reason I'm just not as comfortable crawling around in the back of my truck as I used to be when I was twenty. Just as crawling in a bivy sack works for minimalist camping, they suck if you're stuck in the back due to weather or being sick (you can't sit up and watch a movie or work on your laptop, etc), trying to get dressed when it's cold or raining outside, need to prep your food, etc.
For insulation, I have a piece of plywood on the bed with that gray indoor/outdoor carpet on it. I have a piece of carpet stuck to the front of the bed (I sleep head in) so that I won't be touching any of the plastic bed. I normally sleep on an insulated pad but in the winter I put down closed cell foam and throw a heavy wool surplus blanket over that. You'll want some way to insulate your feet from the tailgate too; I'm just tall enough that if I end up compressing the insulation in my bag and my feet will get cold.
Make sure that you have taped off all of the places air comes in (shine a bright light around in the back while someone underneath it looks for light).
You're greatest heat gain/loss is going to be through the glass so having a way to cover it helps a lot. I use Reflectix with black felt attached. From the outside it just looks like tinted windows but it helps with stealth camping too.
When it's really cold, I tent a large wool blanket above me from the hooks attached to the bolts for my Yakima tracks- like a kid's play fort.
I've got several heaters but the one that lives in the back of the truck during the winter is a small catalytic one that screws onto a butane cartridge (I've got a propane adapter too). I run it for a few minutes before getting in the back and then again in the morning; a few minutes and the back is uncomfortably hot and I do not want to sleep with a non-electric heater going (the only exception would be if I had one of those diesel style that I could put outside the vehicle and pump the heated air into the back). Those 12V heaters are a waste of money in my limited experience and they'll drain your battery pretty quickly. A small Uco candle lantern can actually take a little bit of the chill out; just be careful if you hang it that it's not too close to the carpeted roof.
I've got several sleeping bags for various conditions but if it's not too cold I greatly prefer to sleep under sheets and blankets. When it's cold I use a temperature rated bag but also merino wool thermals and a balaclava. I roll around a lot in my sleep and often find an arm slipped out of the bag so I'll put on wool gloves or mittens if it's really cold.
Air out your sleeping gear and the back of the truck every day if possible.
Carry a pee bottle so you don't have to get out in the cold (make sure it feels distinctly different from any other bottle in your truck so you can find it in the dark).
An awning or tarp, especially off the back, is really handy. A chair and a small folding table of some sort are also super handy.
Harbor Freight moving blankets suck for anything other than moving furniture or as a dog bed- essentially zero insulation value and they tear up. Not sure who recommended one of those but they suck; a real heavy duty furniture blanket would probably work better. I've got a couple of Mexican blankets I toss over junk (camping gear) in the back and they help some- plus it looks like a bum lives back there.