This is a really tough problem. If I lived there full time (mmmmm :) one trap in each building would do the job but it's tough to fight the battle when you aren't there most of the time.
Our building was like swiss cheese when it was built and it was out of control. We've gone to insane lengths to fix the problem and made a lot of progress and it's 90% better but it's not good enough.
Next spring I'm going to try the "adirondack mousetrap" using the peanut butter bucket thing, but even that needs some attendance. What you need is a caretaker who can manage your mouse strategy.
Where is your place?
"You just need to go at that shit wide open, hang on, and own it." —Camp