When my son was in the 4th grade he was invited to participate with "Odyssey of the Mind". (
Click here). This organization is designed to help gifted-talented kids to "think" beyond the box and truly exercise their minds and abilities beyond just the "normal" expectations. My son and daughter both became involved with it, and like good parents, we decided to host a group of kids.
The kids met at our house (usually in our garage) where we coached them with per-programed exercises and activities.
One such activity included sitting in a circle and then asking a question. Each kids was suppose to give a response, going round and round until they couldn't think any more. (the normal expected answers). Then the coaches were to give a couple examples from the program books which would open their minds (outside the box), and then go round again. When that happened, their minds exploded! It was a fantastic experience.
I say all this, because I vividly remember one such question that got the kids so excited, I thought they'd explode. My wife and I still laugh about it.
The question was, "How do you rid of a mouse in your house!"
The standard answers were, "Set a mouse trap." "Get a cat." "Leave the door open and maybe the mouse will run outside."
When the kids exhausted the "expected" answers, the top blew off!
"Flood the house with a fire hose and the mouse will get washed out!" "Hope a tornado comes and suck the mouse out of the house!" "Run the vacuum sweeper hose through all the mouse holes and suck the mouse out." And the real good one that got us all laughing so hard, ... it was priceless!.... "Burn the house down! The mouse will run from the fire!"
OK, probably nothing to do with the OP's original comment and question here, but I just wanted to share!
Thinking of "Odyssey of the Mind" ... (outside the box), maybe one way to mouse proof the RV is to wrap the entire thing with Syran Wrap, and park it in a snow drift where it's 100 degrees below zero!
Edit:
Actually, I like the idea of the steel wool and the foamy insulation stuff. That combination IS thinking outside the box. Folks have used steel wool and other use the foamy insulation. But I think this is the first I heard of using both together! GREAT MIND WORKING THERE ... outside the "box"!