Look for a quarter size hole for rats and smaller for mice. Need to explore under the rig. I used some aluminum roofing flange, cut it to size and Gorilla tape to make sure all entry size holes would be closed up. Only had one rat chew the propane rubber line near the top of the passenger side bottle. Found the little %$^#!! tooth marks with the rubber missing from the back side of the hose when I went to refill the tank. Otherwise the damage was not visible. So go over it and close up the openings.