For most of the interior walls Entegra uses 1/2" plywood with a 1/16" or maybe 3/32" decorative overlay faced with the "wallpaper". The photo below is in the half bath on the wall adjacent to the bedroom. I cut a large access there behind a framed mirror to do some project work. You can see the overlay panel is a separate piece. I put the mirror on a hinge and also use that enormous space for storage.
Since those are separate pieces, if you can remove the overlay, you can cut access holes in the plywood, which will then be covered up when you replace the overlay.
A friend of mine with a '21 Aspire B, had an issue where the lower section of the wall (beneath a wainscoting piece of trim) buckled outward. It just so happened to be on that exact same wall between the bedroom and shower. The fix was to remove the overlay piece which was a hair to big, trim it so it would lay flat and replace. This involved removing the wainscoting and some other trim.
You could also do it by cutting the overlay with a sharp utility knife and using seam tape to hide the cuts when replacing it. On the downside, it's possible the overlay is glued on in some instances.
In any case IMO it's is a good idea to buy rolls of matching decorative seam tape from Entegra parts before they go out of stock for your model year. I have some 2" and some 6" in the two different wallpaper patterns, and one wood grain pattern, used on my coach.
In one instance I had to cut a 4" hole in a wall to get at something. I just replaced the plug and covered it over with the seam tape and it's virtually invisible. If you study the photo below carefully you can probably find the hole, but under most lighting conditions no one ever notices it.
Linear Mode
