I have two options available.

1 (and the best) is to head out to the family properties. A 14' tall, 3' thick wall that surrounds the inner property (it's not on the actual property line itself but a few acres in) that's surrounded by thick, tall and thorny hedges and no trees on either side near the wall to facilitate scaling of any kind. Once inside I have almost 100% assurance no zombie (due to it's location) even come close to the property let alone get inside. Human factor is another issue.

2 (worst, but best protected) - the building I live in has an easily secured staircases via cast-iron bars and the first floor windows / balconies are about 8 feet from ground level, on a hill behind a thick tall hedge. Each floor can be secured with the (I kid you not) steel door that would take a truck to go through and each apartment is similar. In the event of any problems, I live on the top floor already and would secure the building from the top town. The roof is strong enough for the already existing 15' by 25' garden for simple farming which it already does pretty well and a small shed on top with a fuel storage for a portable helecopter (already own one) and a couple of real hang-gliders for others (it's a real hobby).

3 Avoiding all "mass" migrations is a big thing for me, personally.