I towed a new toy hauler home 1600 miles over the weekend. No toy in the back, probably came in at about 3500-4000 lbs. Don't know the hitch weight but was surprised how far the truck dropped when I mated them. I'm def gonna add the Timbren DR1500DQ air bags suggested in this thread. My Anderson distribution hitch leveled things out fairly well, although I was still getting a lot of cars flashing brights at me. The back end ideally would have been a bit higher.
Mileage without towing was close to 20 at best, with the trailer was closer to 11 at 55, 9.5 at 70+. Truck never had an issue or slowed down, even on the passes. As long as I was willing to burn mass quantities of gas, it'd do whatever I asked. The only problem I got with sway was in some fierce winds. I slowed to 55 and everything stabilized.
I'm wishing I had air suspension though. I'd like the 2" lift kit, but with the cap I want to get, my rig wouldn't fit into the garage, dangit. Actually, I may not fit anyways...which if I don't, will make the 2" lift an easier decision. I'm still wondering about an aftermarket air suspension....
2019 Bighorn, 5.7 V8 MDS, 3.21 axle