My adventure started when we headed to san antonio the jayco was in storage and while there a field rat found its way in.... and died.... upon searching for his entrance i discovered the previous owne...
All Purpose Bondo will strengthen the wall backer board and stop any water intrusion. It will also seal around the electrical outlet and provide a strong base for re-attaching the outlet. It is rigid so can crack at joints that flex but can be coated with a flexible sealer like EPDM tape or paint where that is a likely water entry point.