Question about this:
I have a standard canvas 12x14 Davis Wall tent with no floor.  I just use a heavy tarp as the floor and put it on top of the 10" sod cloth that is factory sewn to the bottom of the tent wall all the way around.  This seems to seal the tent to the ground pretty good.
I also have a Cabelas Alaknak 12x12 tent that has a floor.
In early season hunts when temps are warmer I use the Cabelas tent with the floor and don't keep food in the tent and I have never had any issue with mice.  In later season hunts where it gets colder I take the floorless canvas wall tent.  It seems like the colder temps puts mice, and other critters in hibernation and I never have had any issues with mice, spiders, scorpions, snakes, etc... Have I just been lucky?  Do you have problems with mice even in cold temps?