I have used this stuff. http://www.critter-repellent.com/ it's called "Shake Away" and it's freeze dried urine from the natural enemies of whatever you want to repel. Sounds odd but I have used it successfully in properties of mine.
My 49 came with a king snake living in all the mess in the trunk, very little mouse damage he he. Lots of snake skins and snake eggs seemed to really like the car. Just hoping she comes back.
pine sole floor cleaner keeps the pack rats out of our rides here in southern AZ. they hate the smell of the pine i guess