Ok I took some pics of what I did to try and prevent the mice from getting in.
This is an air inlet vent from the furnace. I first covered it with some hardware cloth.
Then I sprayed the expanding foam sealant around it.
I also sprayed the sealer around the wires that went through the floor. But I forgot to take pics of that.
Finally, the wife and I went to the local health food store and purchased a bottle of pure peppermint oil. We then placed several drops on some cotton balls and placed about 8-10 around the 5er. If nothing else it is going to smell great inside!!!! Thanks all, John