Here is the accurate info for a 2015 GM 3500 HD gas dually, truck with tailgate, full fuel tank, 2 average size adults, 7580 lbs., truck with AF 990 camper, full propane, 3/4 tank of fresh water, 2 Lifeline batteries, full of clothes, food and supplies for 2 weeks travel, 12,460 lbs., per CAT scales at Pilot. My truck has 8K lbs. Timbrens, Torklift frame mounts, Super Hitch and FastGuns. Sticker in glove box says to limit slide-in weight to 4913 lbs.. My fuel mileage in the Smoky Mtn. NP has been 9.5 to 10 mpg hand calculated.