I remember seeing a post a while back where a person had to repair a delamination area. He had the same issue, a full wall panel. He opted to cut a vertical seam and remove only a portion. When he reinstalled the piece in the end he simply used a piece of the molding that similar to what was used on the rest of the coach to cover the seam. When done it did not look that bad, but he took time to make a clean straight cut in a location that made sense.
2002 Monaco Windsor 38 PKD Cummins ISC 350 8.3L
2005 Jeep Grand Cherokee w/5.7 Hemi