Dryer Sheets.
We have local mice and have had a few camping. I've used both all natural and commercial dryer sheets. Basically just buy a box, shove a sheet in every corner inside, the back of the cabinets, footwells- I even put one outside under my propane fill cover (though not under any hot covers like the water heater). One at the hinge of each back door etc. basically everywhere I can without just throwing them on the floor (one under the corner of the carpet though...)
The only time I've had a mouse since is three years after the first sheets and they had no scent left (d'oh). I replaced and we've been mouse free again for a year.
It's easy, cheap and smells nice if you don't get overpowering fabric softener sheets.