You can hitch/unhitch at an angle. Just be aware of the side of the truck bed, and you have to have the camper at the right height to re-hitch. If you are hitching straight, you can push under the king pin a little. If you are hitching from a side position, you will simply push the camper sideways, instead of under the king pin. The other consideration is making sure your tailgate does not hit the camper when lowered.
It can be done, just requires a little more attention to details.
2011 Ram Truck 2500, Crew Cab, 6.7L CTD, 4X4, 3.73 Rear