What you have experianced was called "chucking", thats when the camper and the truck are seeming to be going to the same place but in different times. To stop that or reduce it you will need a different style pin box other than the standard one that comes with Cardinals. I put a 5th Airbourne on Cardinal and it stops about 90% of the chucking.
The hitch will not make a difference unless you get a very expensive air ride type hitch. You did not say what size truck you have, but I would first look into changing over the pin box.
3500 Ram 5.9l diesel
08 35 RLT Cardinal
5th Airborne Pin Box