One of the problems you have is the short bed. So even the shortest 8'6" camper will hang about 2' out the back of the truck. This will require a super hitch and equalizer bars or a longer than standard trailer tongue to reach under the camper. Regardless, the trailer will about about 700 pounds to the rear axle.
If you go with a smaller lighter camper without slide, you may be able to pull it off. I purchased a lightweight camper which only weighs 2,400# and 8'6" long. This was my setup on a 3500 LWB 2004 Dodge. I was over my GVWR but slightly under the axle ratings and well under my GCVWR.

If you need to go to 19.5" wheels, then you really need to move up to a dually for the stability and safety.