It depends upon where you park the camper. If you park beside a corn field, you can expect critters. If you are parked inside a barn, or beside a barn, you can expect critters. If you live in a town and park in a concrete suburbia, you probably won't have any critters.
We live in the country, surrounded by corn and bean fields. But our camper is parked on an asphalt drive way, in the middle between the front of the property line and the back. We also have a dog, the next property on both side of us have dogs, and all roam free, and all are hunters. We also have an indoor-outdoor cat that is a hunter, and we've never had problems with mice invading the camper. When we first moved into this house, about 9 years ago, we had mice for a couple falls, until I got the holes plugged, AND we got a cat. But never in the camper.
I think the location the camper is parked has a lot to do with a rodent free experience. Having animals that catch critters is a big factor too, and of course, plugging any and all holes in the camper is a must.
