Just sitting here speculating, planning adequately’s going to be a lot harder than I think most people are allowing for.
I’m no survivalist and I don’t see myself cleaning and eating squirrels, so I’ll have to make do with canned goods and non-perishables for the duration. Seems to me with judicious planning, I could hold out for 3-4 weeks in a zombie-overrun zone; after that all bets are off and I’ll need a contingency plan for breakout to the nearest clear zone as a backup.
If I stick it out in the Houston area, the last thing I’d want to do is be downtown, I think. The problem for me with holing up in an urban highrise is the potential for an uncontrolled blaze sweeping across the city soon after the power and water go out; frankly, in an urban setting occupied mostly by zombies this is more a matter of when than if, IMHO.
My first instinct would be to find one of those houses on stilts that are prevalent near the water here, preferably some distance away from others. It would be easy to place obstacles on the stairs or even just knock ‘em down and have a ladder one can draw up to eliminate the chance of unwanted entry from below. It’s about an hour and a half down to the coast from where I live, but I don’t have the sort of car that can plow through a crowd of Zeds without damage, and it’s too small to carry a few weeks’ worth of supplies, so I’ll need to find a large pickup somewhere with a bull bar on the front. Diesel, preferably, for the mileage and relative mechanical simplicity.
Supplies would be mostly an assortment of canned goods, pasta, rice and beans liberated from abandoned supermarkets, plus maybe a weeks worth of drinking water to get through dry spells. We get a lot of rain here so rigging up something to catch some of it should be a doddle. I will say that if I’m by myself, it’s gonna be a royal pain acquiring all that stuff if I haven’t got some laid in already, and getting it up the ladder, especially if there are Zeds about. I don’t look forward to it.
Weapons? Pump shotgun as a standoff piece, .45 auto handgun for close-in work, and, as someone already mentioned, a shovel. For some reason I really like the shovel. I’m tempted to lay in a bunch of cans of charcoal lighter fluid and a flaregun as well, but the potential for an uncontrolled conflagration from a mess of flaming zombies wandering into the weeds is just too high.
Pretty sure I’ll have to give up on any electric power; getting a generator up onto the elevated deck is doable, but then you’ve got fuel to worry about. I went close to week without power following Hurricane Ike last year, so I think I’d get by OK.