Sorry to hear about the bent frame and I wish you the best in getting that sorted out.
If you want an idea for the back of your C, I would avoid most frame mounted systems because of the issues you have already experienced. I am not sure of the specs, but I doubt that a Class C can carry much weight behind the coach.
A nifty idea I saw this summer at a State park we were at was this solution called a swivel-wheel
. It fits into a 2" receiver as I recall. I like it because the wheel takes up much of the load. They make one and two-wheel systems. Here's a pic from their site ...
You can also consider carrying it on the front using a receiver mounted carrier.
With either front or back solutions, make sure to check the specs for your coach and receiver and match the carrier and bike weight as appropriate.