Why not downsize the stuff and try again. The drive will be same in a C or B or in the car. Traffic is traffic.
Maybe the first trip was a bit big for getting acquainted with a new RV. Second and subsequent trip should be easier. Is there something just an hour away to enjoy?
After a long drive just take it to storage and come back in the car in a few days to get the stuff. If we have a long drive home we try to stay one more night close so the last day is not such a marathon.
If you are set on trading then fine. I am not convinced a B will significantly reduce the work or drive.
As for the repairs just find a handyman to do the heavy lifting or just let it age gracefully. Pace yourself and know your limits.