With the aft interior panels removed, I tried the same approach to repair aft awning mount area that worked in front. Only, without success. The damage was too extensive. I also discovered a double sheet of aluminum in mount area, which I cut away with tin snips to get access to mount holes.

I thought at this point I may need to go to Step 3 of plan and remove the exterior panel. Then, an idea came of using a nice cut-out on the exterior, under the mount itself as a base plate, to...

This task was harder because the aft panels overlap with panels behind the refigerator and shower, neither of which I wanted to remove. Fortunately, access to back of aft awning mount area was under the bed-line, in the storage compartment, which is never seen.

Also, because of the panel overlap, it is very hard to remove an entire panel. So, I decided to make a horizontal cut below the bed line, again, an area never seen. I used duct tape as a scribe line, then cut with a Dremel tool...