the interior plastic behind the passenger door is crumbling..............
If you are referring to the rear panels, they are salvageable if you can't find replacement panels. The '84 I restored about 4yrs ago the rear panels had large holes in the them and most of the section under the X-cab windows were missing, I think I spend about $10 in fiberglass/bondo bedliner and paint to restore them.
Idea of the amount of area I had to work with fiberglass and bondo,
used fiberglass on the back side to reinforce as well.
