I posted this on another forum but will recap in case you missed it. A good compromise is a 2020 F350, 4X4, long bed, crew cab, diesel with 18 or 20 inch wheels and all terrain tires. That combination will get you a 12,400 GVWR. My payload capacity is 4562 pounds, plenty for many medium to lighter weight fifth wheels. It's a perfect match for our new Pinnacle, which after loaded for a trip still gives us around 1K pounds capacity to spare. The long bed gives a better ride, empty and towing, in my opinion plus you get a 48 gallon fuel tank vs 34 in the short bed. A biggie in my books. I'm really pleased with how it tows the Pinnacle and it drives smaller than the dually I had before this truck. May be all in my head but I think it is because I'm not having to account for the extra 2 wheels in the back.
JimT
2020 Jayco Pinnacle 32RLTS, 2020 Ford F350, Platinum, 6.7 diesel, 4X4, CCLB, SRW, 12,400 GVWR