I also am not a fan of the bumper style mounts, just search here and you will out why from lots of people, this has been discussed over and over.
I would suggest something like this: Pop Up Camper Bike Rack
or a similar style that sits on top of the camper itself. When we started camping we had a pop up and we put a free standing rack on top of the camper that strapped down and hook to the bottom frame of the camper on both sides. I will say that worked well for getting the bikes back and forth but it was a bit of a pain loading and unloading, would have preferred the bed of a truck, but we did not have one at the time.