I've tried the mothballs...the peppermint...and other anti-mouse systems mentioned in this forum...but the only thing that WORKS (for me, anyway) is the cheapo wood/spring/snap trap.
I have 2 next to the generator, one in the (outside)plumbing compartment, one in the outside fridge compartment and 4 inside, various places.
Usually, I get 3-5 by now...and keep the peanut butter flowing. However...as of this moment, this year, I have none. The traps are there...just waiting......
The generator area seems to be the favorite...where most are caught. The outside plumbing is next. Inside...only got two. In 10 years. The outside fridge...never. But y'never know. All the traps get checked every 2 weeks, when I go to the motorhome and start the motor and genny.