We full-time part-time, that is we travel about half the year and the other half we stay home. When traveling we tow a 40 foot Montana 3790RD fifth wheel with 3K of pin weight and 16K of tow weight. The TV is a single rear wheel, standard bed, 3500 Longhorn with the Cummins, and the 68RFE tranny. I don't recall my payload number but I think it is just north of 3.8K.
After 6 seasons of towing and more than 34,000 miles traveled, we have been issue-free, with no problems. I made the right choice when it came to a tow vehicle. Hands down the Cummins, single rear wheels, and the Longhorn (or Limited) trim, and rear air leveling suspension. Why?
The diesel makes towing fun and effortlessly including the hills going up and down. The fuel economy is great with my averages between 11 and 13 depending on wind load.
Single rear wheels, ample capacity, and control. The issue with duals is parking, particularly in sightseeing venues. Also, many places we visit are down long narrow, and often dirt/sand-covered roads. Way too tight for DRW.
The Longhorn and the Limited trim offer very comfortable seating surfaces, much different than the Laramie. You will appreciate the seating after 6 plus hours of traveling.
I also added the BD Diesel 2 wheel drive low range kit. This allows the truck to be put into 4 wheel drive low without engaging the front axle. This gives you the power to maneuver when parking your camper without using the accelerator and prevents steering binds.
If you chose a fifth-wheel camper, either order the long bed (keeping in mind parking issues at venues) or get a slider hitch.