When we towed a Travel Trailer I couldn't see behind the trailer when we drove, so it is no different with the Class C. We have a backup camera that comes on automatically when in reverse, but can be turned on at any time. Our backup camera is there to monitor what is directly behind the motorhome, generally when backing up. I do monitor the bikes from time to time while driving. It only shows maybe 8 - 10 feet from the back, so unless I'm stopped, if I see someone in view, I'm probably getting hit.
Just make sure your mirrors are positioned properly and you'll be fine. It is weird not being able to see what is behind you, but you'll get use to it.
-Michael