So a 1 ton DRW could conceivably be not enough truck for a 4000# camper considering GVWR although GAWR of the rear axle might be ok. The above figures were using the new Bigfoot 10.4 of 4083#, with water, gen set, battery, and no rear steps and nothing else.
Just something to chew on.
Very easily..Take a DRW with 5,000 lb payload and fill up the tanks and ad your tools/people and gear to your pickup,and you will be over GVWR with that 10.4 Bigfoot loaded to camp.
My 1994 F-350 DRW has 4600 pounds of payload and I carry a Lance 9.6 with an accurate sticker weight of 2582 pounds empty..Full of fuel/my gear/tools/tire chains and horse mat,I am just barely under my GVWR with the TC loaded for camping..Ad my ATV trailer and I would probably be slightly over with that 2582 pound empty TC..
The axle weight with that camper is 6,000 pounds and some change and the axle is rated at 8250 pounds, easily upgraded to 9750 pounds with a gear swap, if I wanted.
So yes,even a dually can be overloaded with a smallish TC if you go by GVWR.