Not sure how I didn't get critters this year, but we didn't.
When I put it away for the winter, I took a good look underneath and taped up anything that wasn't sealed already.
When I plugged it in, I got out the old duct tape again and taped up EVERYTHING around the cord where it goes in the trailer. I guess it worked, since we didn't find any mice.
We "opened" the trailer up last weekend to get ready for our first trip in a couple weeks.
2015 32 Foot Rockwood 8289WS 5th Wheel
2013 Chevy 3/4 Ton TV