Hi NJNS,
We started out by ensuring that the unit was no longer taking on water. We had all the window seals professionally replaced, and continued the previous owner's frowned upon action of applying a sealer to the entire roof. We figured that after 40 years we just were trying to keep it going and dry. Then, for remediation of damage we did three things:
a. We had new ceiling panels mounted over the existing ceiling. We used this opportunity to install new LED
lighting as well.
b. Inside the front headwall of the cabinets, we sanded everything to a smooth finish (very fast) and painted inside the cupboards.
c. Where we had veneer around the
windows that was damaged from water we used a combination of filling/painting, and in some areas we were applying wallpaper/tiels anyway, so it covered these defects.
If you zoom on the attached photos you can see how the headliner is secured with trim/molding in addition to brads.