RV Repair: Interior repair, toyota dolphin, metal siding

Question
I have an 85 Toyota Dolphin with water damage to the interior left rear side and rear panels. The wood strip pieces are completely rotted away. How do I repair this without removing the exterior aluminum?  Also where do I find replacement matching paneling? If I remove the aluminum,then how do you do it?

Answer
Most motor homes are constructed of a layer of wood, a layer of foam and something (metal or fiberglass) laminated to the exterior. The whole panel is made in a "jig" under pressure (glue and heat).
The only way you can restore the original condition is to replace the entire panel.
I have replaced components of a panel without removing it but that takes lots of patience and experience.
I doubt if the original metal siding is available anymore, the manufacturer is the only one that would know.