I stored it in an open farmers field, covered with my Atco cover.
I've had the trailer for 4 years and never had any mice enter before this year.
I make sure to give it a thorough clean, make sure there isn't any food anywhere. Then I put bounce sheets all over, between cushions, drawers and cupboards, etc etc.
There are 2 things I didn't do this year, mostly because I was rushed that day... Firstly I didn't remove all the dishes from the cupboards... Everything was clean but usually I put them in a few totes. Secondly I didn't put any steel wool around the bottom entrance of the slide out, the entrance for the electrical cord, etc. So I'm not sure that's where they came in through, or if it was scent of the dishes that attracted them.
Either was lesson learned. We were lucky they didn't chew anything up like the sofa or dinette pillows. That would've been an additional nightmare.
Bummed out enough about the damaged bunk!