You'll get a better towing experience with a fifth wheel in a shorter overall package. Stay within your axle and tire ratings on that truck (6000/6500) and you'll have no issues and it's perfectly legal as long as you are properly registered with your state. Your truck is identical to a non-Aisin SRW 3500 other than the rear coils, and the axle rating is only 500 lbs lower than the 3500. The only reason the payload is so limited is the class 2 10k GVWR limit.
As far as I'm concerned once the travel trailer hits the length of the smaller fifth wheels (30-32' these days) you're better off in a fifth wheel.