I don't think it'll work with a 5'er. Fifth wheel trailers are designed to be towed with trucks with a somewhat standard bed and box height. Even stock Superduties have compatability issues with some 5th wheel trailers. You need to have at least 4" to 5" of clearance between the top of the bed and the bottom edge of the RV.
If you try to mate-up a fifth wheel and a truck that has a 6" lift kit, you will have problems:
1) The trailer will not be in a level towing position and will be in an excessively nose high attitude causing possible handling issues.
2) The angle will be severe enough that while you might have the required clearance of 4" to 5" at the mid point on the sides of the truck box, you will not have adequate clearance along the tailgate area.
You can have a 6" lift on your truck or you can have a 5th wheel RV, but you can't have both unless you put a " 6 inch lift kit" on the RV trailer also. But you don't even want to think about going there for safety reasons and verticle clearance issues.
Like the others have already recommended, go with a travel trailer.