One way or another you must get rid of the mold completely. Probably the outside filon is laminated to a luan wood. I used one of those multitools to remove the foam, eliminate the mold with mold cleaner and sprayed with a mold preventative. All available at lowes. I then re-glued new foam onto the exterior luan and finished off the interior. It was a long and tedious project. Any other component that could not be replaced was cleaned with mold cleaner, and coated with an epoxy coating(after I used a heater for days to completely dry it out.
PC epoxy My rv was so bad it turned into a whole summer project.
Could not have done the project with that multitool. It was invaluable.
Best of luck to you.