I spent 6 weeks from middle of May on up at Lake Tahoe in a forested RV park. Millions of critters. Even had bears walking by. But mostly mice everywhere.
But I didn't have any inside my RV. What I did was cut a bar of Irish Spring deodorant soap into quarters and place 1 quarter on top of each tire. Then I bought 4 bags of Fresh Cab (Amazon carries it) and placed those inside the RV.
No mice inside the RV whatsoever. Also had backup mouse traps which I'm fine with using if I'd have found any evidence of mice, but I didn't so I never put them out.