I'm fly with most anything that goes, really. I'm up for the Day One idea, as it'd be interesting to see the characters' reactions to the transformations as well as how they cope with the cataclysm. 

Though if we are in a city chunk and survived, wouldn't that mean pretty much the rest of the people on that city chunk survived as well? We could be facing a group of thousands, if not hundreds of thousands of people if we choose to appear on an actual "city". Why not a National Park of sorts?