The problem is you bought a 3/4 ton truck and then started looking at fifth wheels. You need to take the truck to a scale, and see what it's weight is. Find the GVWR on the drivers door, and subtract the empty weight. You will get a cargo rating. Take away the 150 pounds for the hitch, what your driver and passenger weight is, and anything else you might carry in the truck.
You might have a 8,000 pound truck and a 9,200 GVWR. That is no good for towing a fifth wheel, as you can only carry 1,200 pounds, barely enough for a travel trailer.
Fifth wheels have a heavy hitch pin weight in addition to the hitch that is around 150 - 200 pounds of steel! So a 10,000 pound fifth wheel typically has a 2,000 pound pin weight.
While a travel trailer the same length might have a 10,000 GVWR and 1,200 pound hitch weight. The hitch weight distribution system might add another 75 pounds too that weight.
So check the weight of the truck. If it is under 7,500 pounds, you might have a great truck to tow a small and light fifth wheel. 8,000 pounds and you have to be careful packing the truck to avoid overloading it while towing a travel trailer.
Good luck,
Fred.
