mice in 19' hideout already this fall!

[raybren2004]

We were getting our snowmobile out of storage and decide to check in the camper. to our surprise, mice have been taking up residence only after about 6 weeks! we just bought it this summer new and already mice? we had a 1969 towlow and never ever mice. where are they getting in? and why would an outside recreational unit not be more mouse proof from the factory? very upsetting!