Why would a 1 ton 3500 be squatting with a pup up? Don't get that. Your camper weight has to be about what mine is (2200 pounds) wet (no gear just propane and water). Mine never squatted the truck at all. Even the overload leaf is 4" away from the perch block. Granted I have air bags but that is with only 5 pounds in the bag, where they are at rest (no load) all the time.
After looking at the Timbren (aka: rubber ride). I don't think you'll be very happy with the unladen ride. They look to me to be a hard riding alternative when empty. Your kidneys, not mine....lol
I believe I'd go with max inflation in the rear tires for starters, then air lift bags (like I have) and then a sway bar. One thing about air bags is, when empty you can deflate them for the OEM ride and when loaded, you can air them up to level and and increase the capacity and they reduce sway.
Your choice however.
Kind of puzzled about your suspension and it sagging. Never had that issue with my Ford at all. Really, not even with the Lance in the bed, did the truck squat much. Maybe an inch or 2 at most.
Sit in with the Palomino is maybe 1/2" at most. Could be I have a stouter suspension than you do, not sure.
I think the Timbrens are a mistake but again, it's your money and your kidneys, not mine.
