[KeithInUpstateNY]

Foam is messy and hard to use for small gaps. I used aluminum foil tape to seal all the edges of the Coroplast.

If you have a traditional hard wired electrical cord stuff a copper pot scrubber in the port. Steel wool will rust.

I haven't had any mice get in since I tightened everything up.

BUT, to save yourself a potential mess if they do get in remove anything that is potential food (any bar soap, they chewed a bar of Pears glycerin soap before I got things sealed up) and potential bedding (paper products, clothing, linens, rugs, etc.). If you don't have room to store everything at home get plastic bins to store these items in your trailer.

You're in snow country it looks like, so if possible raise the tongue of the trailer to aid in run off when the snow does melt to reduce the risk of ice dams around the AC, vents, etc. and lighten the snow load, especially if you don't have a walkable roof.