Sagging leaf springs? Epic cross country tow in my future.

Hi, I'd like to get your opinion on whether or not my leaf springs need to be replaced. They are almost completely flat with no load on the truck. Adding even a 500lb motorcycle sinks the rear end considerably.

I have a cross country move coming up and will be towing right at the 5000lb limit.

Should I replace the leaf springs with a new heavy duty aftermarket variant or add Timbren Suspension Enhancement System for the extra tongue weight?

Ideally I want to eliminate sag and minimize trailer sway.

I will also be replacing the brake pads. They are due to be serviced soon anyway. Any recommendations for pads which will minimize brake fade on grades with a trailer attached? Trailer has electronic brakes, but I want to maximize the truck's stopping power anyway.

Has anyone here towed 5000lbs through the northern rockies? Across Idaho and into Oregon. What should I expect in terms of grades?

Thanks!

 

Your springs look just like my springs. I've been shopping and trying to decide whether to go with Timbren, Air Bags or new springs and there are folks that have good stuff to say about all of them for the same application. The Timbren SES seems to be the cheapest. I haven't decided yet.
As far as the grades coming through MT, ID and OR... Depends on where you are headed. I travel to the coast about twice a year from MT. If you are headed west on I-90 your first big pull will be Homesatke Pass outside of Butte. It's a steep grade of roughly 8-10%. There is always someone broke down or over-heated. From there headed west your next big pass will be Lookout Pass on the ID-MT border. It's a little gentler than Homestake but a longer pull. After that is Fourth of July Pass in ID near Couer d' Alene. That one isn't bad at all, but still a pull. I'm not sure of your route, but if you're headed into OR from WA out of Ritzville you won't hit any other big passes. The next really nasty one headed west would be Snoqualmie heading toward Seattle.
I hope that helps.

 

As for the route, we're taking I-80 from Cleveland to Salt Lake City, then NW on I-84 for a stretch before HWY 20 W in OR.

I got second and third opinions locally. The mechanics I've spoken with agree that the suspension sag is extreme. The truck must have been overloaded at one point because the base leaves in the pack (the ones that are supposed to be more or less straight) are actually curved downward. I ordered the Heavy Duty replacement from General Spring. Will update with comparison pics once I have all the parts out of the truck.

Also ordered drilled/slotted rotors, Wagner SX799 Severe Duty brake pads, new tires (General Grabber HTS) and a fresh air filter. Once it's all installed I feel like I'll be all set for the long haul.

The Timbrens are cheaper, but they seemed like only a half measure.