I would say leave it unlocked. I have no first hand knowledge of where your cabin is, however, we do have some experience with unattended property.
We have a small cabin near Sequatchie, TN. We used to keep it locked down with the windows boarded up and the only door locked. Every time we went back the front door had sustained damage and the cabin had been entered. One time they ripped out all of the copper wiring. There is a full-time resident nearby but he was unaware that anyone had been there. Because of the elevation the county has a water tank and access easement so there is regular traffic to the property. We built a small shed out of concrete block and had the water and electric connections put there. We have not had an issue with it being vandalized. In the summer of 2010 we decided to leave an old RV trailer on the RV pad we had there. Well, last February (2011) we checked in on the property only to find the RV gone. We contacted the local sheriff and discovered that they had confiscated the the RV. If seems that it was being used as a meth lab. We could file the proper documents to get it back but they told us we would not want it back. After seeing the pictures they were right. When it comes to the drug trade, all bets and common sense get thrown out the window. It does not matter what side of the border.