If you go by what Dodge wants, 16,000 lbs GCW with 3. 54 gears with manual trans or 17,000 GCW with 4. 10 gears with manual trans. GCW=gross combined weight, meaning total for truck, trailer, and people. Also you need to figure your pin weight in with the rear axle limit and the trucks GVW. Rear axle limit and trucks GVW can be found on the drivers door label.
My truck weighs 5,580 lbs with me and a full tank. My GCW is 16,000, minus my 5,580 truck weight means I can tow a trailer of 10,420 lbs. My 5ther will gross to 10,050 lbs. So with me, truck, full tank, trailer to it's max GVW, and a passenger, I come in at 190 or so lbs to the good. But I don't carry enough crap with me to max my trailers GVW. Normally with my trailer ready to go, it will gross about 8,500 lbs and end up with with about 14,300 lbs GCW.
It's all in the math and knowing your true weights. Never trust the RV's empty weight rating. Pay a few bucks at the truck stop for the CAT scales. I would suggest going by the trailers MAX GVW when figuring your numbers to be safe. King pin weight can be 10% to 25% of the total trailer load.
Why to follow the trucks limits? Truck will perform better, fuel milage will be better, truck will last longer, and it'll be safe and legal.
Don't care about the above? Load it till it breaks. :-laf
Also big and nice (heavy) 5th wheels are sweet, but remember, the heavier the trailer, the less fuel milage you'll get and the harder your truck will need to work to pull it.
Earl