Easy to catch a mouse with peanut butter...
Google image
When you go dump the trash can outside somewhere the mouse in most cases will likely beat you back into the trailer haha...
Just poking alittle fun with your mouse problem...
I had to seal every hole I could fine and I still get them occasionally...
In my case I turn on lights inside my POPUP trailer at night and go look under the trailer and see spots where light was showing through the floor...
My biggest place was the shore power cable lid. They would climb up the shore power cable and get inside...
I also had a seal problem between the pulled out tent bed and the popup trailer wall. I could bend over and look straight out where the oem seal was located and see daylight with hugh gaps in the seal strip... This also let in night bugs and all... I finally came up with a better seal arrangement to solve that problem...
You will probably have better luck containing them with a better sealed large trailer. My popup is just to open to do much good...
Roy Ken