Well , that was a surprise. I took the door apart to replace the luan interior face with the same maple plywood I'm using in the rest of the trailer, and after I took the frame off, it literally disintegrated - rotted to a pulp. I'm grateful I found out now and not when I was installing the window, or even worse, on the road, plus the old door was just the aluminum skin and the luan with foam in between. I spent the afternoon rebuilding and an hour getting the adhesive that glued the foam off, and polishing the aluminum frame. As long as I can get the lock mechanism back together, it's going to be one sweet door. Ordering the window tonight.