Before I do that, I need to resolve the issue of the setting. I was originally thinking of Los Angeles, but I'm not so sure. I'm going to see what you guys think, so here is a list to pick from. Keep in mind that, from your point of view, the place seems totally deserted, at least at first. That will give you the entire area to run around in. Using a place like LA might be a bit too big, but it would be interesting too. And if you're wondering how "boundaries" are enforced, you'll find out in the game.
Anyway, here are the choices:
• Los Angeles, as already mentioned.
• A midwestern, small town, the antithesis of LA. It may take some time before you even notice people are missing, but a much smaller area to work in.
• A cruise ship. Completely contained, out in the open water, and an even smaller area.
• Manhattan. Same dense city atmosphere as LA, but since it's an island it already has established boundaries. Still, the same too much space problem, though.
• A particular building, like an office building, hotel or apartment. This would give a nice, "we're trapped in here!" feeling, though without the eerie city without people vibe.
• A college campus.