I am resurrecting this thread to provide a couple pictures regarding the possible ingress of mice into the Cali cabin.
Quick backstory, we began a month-long trip beginning on Vancouver Island (our home) in Canada, and running across the northern interior of British Columbia. Our van was parked for six days while we did a sea kayaking trip in the Broughton archipelago, and then we took a ferry to the mainland and began camping every night across the interior of BC. About three days into the mainland part of the trip we heard scurrying in the cabin while we slept - sure enough, we actually saw a mouse. By the time we set up a ‘human powered trap’ and caught the first one, we noticed there was actually two in the cabin. We were unable to catch the second one, so once we arrived at a large enough town, we purchased a couple simple snap traps. To make a long story short, by the time we reached the beginning of the forth week of our trip, we have caught no less than four mice.
Having read on the forums here that the only possible ingress site being mentioned was the waste water drain, I took the opportunity at a decent campsite in Fernie BC to at least temporarily plug this possible ingress point (this was today, just an hour ago from the post).
The first picture shows how rather large that opening is and the second shows my extremely rudimentary and certainly only temporary solution, where I used several layers of duct tape to close the opening. Of course, as an early model Cali owner in Canada, duct tape is an important on the road repair tool.
Once we return home I will swap out steel wool and speed tape (along with peppermint oil) for the temporary fix.
In the meantime if we get another unwanted ‘guest’ during the last 6 days of our trip, it should be easy to confirm this as the entry point.