We only had mice as a problem one time with no real damage (other than front mattress in our 2720 smelling of urine and droppings present). We took care of the mattress cleaning and left it out in the sun afterward to really make sure it was cleaner.
I concur with the peppermint essential oil but instead use blue spruce or Christmas tree essential oils on cotton balls and tiny pinecones that I keep in a cleaned out canned chicken breast can. We keep it in the bathroom and all smells fresh with no more mice. A friend uses the Walmart brand of pine scented cleaner and sprays his motor home under carriage and wheels every so often. His MH is kept outside the garage we rent from him for our TM. He thought because the black snake hanging around is not seen anymore that the mice are more prevalent.
We also carry a box of fabric softener sheets to keep ants from invading. They seem to find ways in through the bed end corners and congregate on the back end by the bed bar latches! I must have killed a hundred of them last time, attracted by the water leaking out the hose coupling. They will also climb a hose and come in by the front bed end where we can see a small area of daylight. I try to stuff a piece of hard foam rubber in that hole.