I've always heard never to use any kind of Decon-like product. The mice eat it, then crawl into some cubby hole and die. Then the smell starts. True or not ??
My philosophy was to do something so they would not come in, or at least leave after the first visit.
I used to put mothballs everywhere in my pop-up before storing it for the winter - I used a whole box, putting several in each dixie cup, then putting the cups in drawers, etc. including outside behind the hot water heater door, and in the battery box. Usually stored inside but at least once it was outside in a field (Iowa). I never had any critter problems. Just air it out for a day or two and good to go.