We've full timed for ten years and usually spend three months in a summer and winter location while volunteering. We've dealt with mice and wood rats and have had good luck with the following:
Fresh Cab - works great for us on mice.
Motion Sensor Lights - I bought four on Amazon for $50. Two are placed underneath, two on sides of MH. They're sensitive enough that a mouse or rat will set them off. Seems to work well, and are great for security.
Xmas Lights - Rodents will get acclimated to steady (rope) lights. I bought an 80' string of flashing white lights for $15 on an after Xmas sale. Looks nice and scares the rodents.
As an aside, I've had fellow RVers complain about rodents, but still have bird feeders with seed. The seeds on the ground attract rodents; use suet instead.
As a last result, use a quality snap trap w/peanut butter; live traps don't work.