If this is a single rear wheel truck, then the tires will be the main factor in your ability to tow that rig. You will be at the max +/- some lbs. Check the side wall of the tires for max single tire weight rating. Multiply by 2 and that is the max weight the rear axle can handle. If it is less than the RAWR sticker, get better tires. You may have the AAM 11 1/2 rear axle in your truck. If so, that is the same axle used in the 3500 duel rear wheel truck and is only limited by the tires and RIMS.
As for towing that much weight, exhaust brake, air bags, rear sway bar and air hitch or air ride pin box are a must. The 5th is a balanced on its axles from front to rear. The more weight you have rear of the coaches axles, the less weight on the pin. I have no problems towing a 15,000 lbs Sanibel 3600 after installing the factory 18" J rated rims from a 2014 Ram 3500. The new tires added 900 lbs more load capacity to the rear axle. This is still less than a 3500 drw, but keeps the truck from being overloaded. I have the 11 1/2 AAM axle.
The air bags add a third point for weight distribution on the frame and allow adjustments to the ride height.
A rear sway bar is a big help with or without the coach.
Driving down a 6% grade, exhaust brake is a must!
I am sure many others on this forum will tell you I am nuts, but this is the mods I installed and they work well on the truck.
I install a Trailaire pin box on the coach to reduce the shock to the frame of the coach and truck. This helped with reducing chucking.
Now, let the fighting begin. Where are the weight police?