And yes, cats stink too! I have 3 of them. They keep all the rodents smaller than them chased off.
As far as 'possums and 'coons, well they just watch them. I have to medicate them myself. But that is news for a different thread.
To keep mice out, stuff steel wool into any little hole, crack that you can find under, on the side, on top of the rig. You can find steel wool near the rodent poisons or traps or in any hardware store. Don't be humane to the mice, kill the little B__TURDS! Forget the box traps or the sticky pads. The best thing is the ole spring trap with a peanut/pecan/peanut butter as the bait. Guaranteed!!!