The largest fifth wheels weigh 14,000 to 16,000 pounds and you won't be towing them -- or stopping them -- empty. They typically are more than 32 feet long and have several slide-outs (sections that slide out to make certain sections wider when parked). Some have granite countertops and tile floors in the kitchen. All that rock adds weight. You're probably looking at three axles, sometimes four, and six wheels at least. Get the biggest truck you can find with the largest diesel engine. Do your homework on the camper discussion groups. People generally learn from their mistakes when they get stuck on the road with a blown engine or transmission. The more weight you're pulling, the more weight, power, suspension stiffness and brakes you need. In this class, you need at least a 2-ton truck with a dually rear-end. Many people with this large of a tow go for a mini-tractor or even a full-size 18-wheel tractor. If you're thinking 1-ton, that will work if you're a snowbird who only pulls it twice a season. Don't use a 1-ton full-time. Experience shows that it will wear out the truck, especially the transmission.