My 2005 F250 had a 4000 lb camper in the back while towing an 8000 lb trailer. You will find the stock rims and tires will be your first weak point and the suspension will be your second. The truck axle and frame ratings are good for over 9750 lbs. I used the 20k lb rated SuperHitch receiver with the 28" SuperTruss double extension and a Harbor Freight 10k lb WDH. To handle the 8000 lbs of rear axle weight, I ran 19.5" rims rated at 4500 lbs each, PR16 tires rated over 5000 lbs each, upper and lower StableLoad products on the factory camper suspension option and airbags inflated to about 50 PSI.