Yes a Dually is needed for the weight of a dual slide camper. The added weight of the diesel is up d=front so not as bad as it sounds but will reduce the total payload weight. I have had gas and diesel duallys.If you go that large you'll need a 3500 dually minimum. These campers are heavy and will overload your truck and tires pretty quick. A gasser has a larger payload than diesel also due to the engine/tranny weight.
Gas is for hauling ass, diesels are rattles for big babies. Has anybody seen my pacifier?:grin2: