Got the panel off last night and found a few issues.
First noticed two big cracks in the plastic door panel backing. I guess GM didn't run these things through any computer stress modeling analysis and tried to use as little plastic as possible. Man this stuff is thin and brittle. Could just be age I guess. Decided to try and repair them to get a bit more life out of them as these are expensive to replace and new tires are next on the procurement list.
Flipped the panel around and noticed the cracks went all the way to the top of the door panel.
Took a piece of aluminum and riveted it in place across the top cracks to keep them from expanding.
Next, took a piece of scrap plastic and made a support that I could epoxy over the crack on the panel backside to secure it.
Epxoy and clamp support into place and let cure.
Both big cracks repaired.
Here's a better look at where the door covering is separating from the panel. I put epoxy in the opening and clamped in place over night.
I don't have a picture yet but the results looked OK. I'm not sure how long it will last because the covering backing is foam rubber and the covering had developed a memory because it would not lay down on it's own. It look OK for now though.