We do a stint with the Forest Service every year.  Last year, the mice were everywhere.  This year, we  put 
Fresh Cab Repellant in and under the interior cabinets, and 
Tom Cat Bait Chunks  in the compartments and under the hood.  No problems at all.  I also use the bait  chunks around the garage where we store the coach and under hood when it's parked there.  It's worked so far.
P.S. Don't put the bait and the repellent in the same areas.  The bait has an attractant in it and will draw the mice to it.