Alaska trip 2019

I towed my 20 ft travel trailer with my 2014 4Runner from Valdez, AK to California in 2017. My only casualty is a huge chip in the windshield. The roads were fine for the most part. My route was through Banff and Jasper which I would not skip as they are awesome. We took about 10 days through Canada camping and hiking, definitely sightseeing. I never exp a fuel issue avg about 12-15 mpg. As stated before, I did not skip any fuel stations and carried a 05 gal with me just in case. Plan to cross through towns during business hours though. Someone asked about warm month mosquitos, they are terrible and eat bug spray so plan accordingly. I lived in AK for several years, watch out for wildlife on the roads. They are everywhere! Pack warm clothing just in case, they were still skiing at higher elevations. I hope this helps. Safe Travels!

 

You won't have much problem with mosquitos, (because the air is cooler already) maybe a few flies mid to late October.
For mid to end of October, do expect snow as likely on your route, and freezing temperatures enroute north of Prince George, BC (halfways north thru BC) at that time of year.
If you are camping, a good supply of clean water (ex 5 gallons), keep it inside your truck once it gets colder, and you should be good through the night to have water in the morning. I switch to winter tires by the end of October for the mountain passes, and I live in southern BC. Have a good insulating thermarest or equivalent under you, even if sleeping in the back of your truck, as that is where you'll have the most heat loss, and a toque for your head + dry, thick wool socks for your feet while sleeping, and of course a sleeping bag that can handle below freezing temps.