Sciencemile:
I've personally had enough of the country and Nature; if I'm going to deal with some sort of Apocalypse or another, I'll take my chances in the Megalopolis of Concrete.
I'd run out of Zyrtec eventually if I didn't stay near a pharmacy, and without Zyrtec I'd die from fatal allergic reactions in the Spring/Summer anyways.
I don't think the country is for everyone.
I read one blog that came up with a very good compromise to your concerns. They set up an "escape" in a smaller town within driving distance. Such as they rented a storage locker, and filled it with supplies and gear in advance. They scouted apartments, and shelters that are for rent, and kept the information handy.
Basically, if an emergency came up, they could leave within minutes, and get somewhere a bit more quiet, and away from a large city. They had plenty of supplies to camp if need be, food, and cooking equipment, first aid supplies, extra gas, etc.
One thing that has me getting away from the city was the fact that if something really bad happened that really disrupted the city, such as earthquakes like in Chile, the distributions channels are affected. For example, people in Chile were rioting over food.
So, since large cities import so much, if a large city is affected, they will also be out of supplies very quickly. I've heard suggestions that many supermarkets would run their shelves dry within days without constant importing.
Worse, in cities, it seems when some emergencies occur, looting just seems to take over. So you'd need to protect yourself if you're still in the city when some emergency happens.
I'm not sure what plan you might have to protect yourself, but it seems reasonable that some looters may be armed with guns, machetes, bats, clubs, crowbars, multiple attackers, etc.
You don't have to be armed with machine guns, just able to make it not worth their while to go after you.
Basic question for you science. Do you have extra zyrtec on hand? Such as a month or more at all times? If it's that important, you would want to make sure that no matter what, you'll have your supply.