As Jim stated, if there is not any "backer lumber" for the left end (looking at the trailer), it will be very difficult to mount securely. I guess you could drill holes through the wall and install bolts all the way through to the inside. How well you could tighten them and not crack or crush the inside and outside walls, I dont know. If your coach has fiberglass outside walls, they are very thin and only have hard foam and 1/8" plywood inside. Before you do anything, I would call HL, have your VIN# handy and ask if they think its possible to do.