Right Rear torsion bar bracket. Lag bolts pulled out of wood frame.

I have a 3023 built in 2001. Three of the five lag bolts holding the right-rear torsion bar bracket to the main camper shell pulled loose making a loud bang. Two aft bolts remained connected causing the bracket to bend at a 90 degree angle at the point where the torsion bar passes through the bracket. By opening the camper shells and using jacks, metal bars and c-clamps, I was able to straighten the bracket enough to put over-sized lag bolts back in. After a day of the camper being back in storage, the lag bolts are already starting to pull out indicating that the wood inside has rotted.

Has anyone had to deal with this problem? The factory people said to re-drill the holes at an inboard angle and use long bolts with a backing plate on the inside. My concern is that if the underlying wood is rotten, won't the skin of the camper become distorted when I tighten the bolts?

I'm considering a flat metal plate on the outside large enough to secure the bracket to the camper. Anybody have any suggestions, advise, etc? Steel vs Aluminum? Bad Idea?