With that kind of damage I would consider using some Decon; the stuff works, is reasonably safe for non-target animals, and is effective. If you have a structure, or area that you park in regularly, you might also consider tin cats. I find that these are quite effective long term solutions for mice. You only need to bait for the first mouse; a bit of apple and peanut butter works. More mice will follow, and the cannibals will eat the previous entrants. Once every few months empty the container of whatever remains, and rebait. I've used the same tin cats for over 20 years with great success.
Renais

cats.

the humane society has lots. cheap.

Mouse traps. Find a place under the hood (top of air cleaner) for a trap or two. You may need to leave the hood ajar to make clearance for the trap. Peanut butter makes good bait. After you get ahead of them set the traps without bait because you don't want to lure them to the vehicle. Works for rats too but you need a larger trap.