We had to leave our Destination Trailer parked, for an unknown amount of time, in an area we knew had mice. I purchased some
copper mesh to stuff into any openings on the trailer. I had heard that steel wool works well, but I figured it would probably rust out, so I went with the copper mesh. I rolled it out and then balled it up like a steel wool pad and shoved it into every opening I could find under the trailer. I found half a dozen places in the underbelly that were large enough for even a rat to get through.
Because of the pandemic, the trailer was parked for 18 months. When we finally got to it, the only evidence of mice was a small nest at the top of one of the 30lb propane tanks. It drove me nuts not being able to inspect the TT for 18 months and was pleasantly surprised to find no mice or evidence of mice inside the TT. Spiders yes, but no mice.
-Michael