Complete mice solution
It took less than a day to completely mouse-proof the trailer. Prior to that we were plagued with them. Fortunately, they mostly kept to the kitchen area and ate the labels off all the cleaning supplies. When we tried trapping them, we always got three or four, but the woods had way more mice than we had traps.
The key is to first go under the trailer and mouse-proof every possible entrance point. I got a bag of #3 (coarse) steel wool pads. At each place where a cable or pipe penetrated the floor, I unwrapped a pad and re-wrapped it around the cable/pipe, securing it with a cable tie. I did this regardless of whether there appeared to be a gap around the penetration or not. I had a big sheet from a cardboard carton to slide on and it wasn't too uncomfortable.
Then I went to the top side and took care of the penetrations at the toilet feed and gas feed for the range. These were pretty tight, so I tore off segments of the steel wool and stuffed them in with a flat-blade screwdriver.
Haven't seen a mouse since, and that was 3-4 years ago.
Bronze wool pads (if you can find them) might be better, since they don't rust.
Sticks and Bricks: Raleigh, NC
2008 Cherokee 38P: at Ivor, VA permanently