The last AW game I ran was set in a post apocalyptic early 80's Manhattan. I didn't even realize that I was ripping Escape from New York in a few ways.

Our game's structure was set up amongst rival gangs that control the majority of the ruins of Old New York. The gangs generally have 10 to 18 members (a few are bigger, some are smaller) and patrol a few square blocks (most of the cityscape is horrible devasted and dangerous to travel above ground in, the majority of communities are built on the subway hubs and use them as highways, and are generally populated by 40 individuals).

When we developed the city we wanted to have a few larger hubs of humanity on the island (upwards of a thousand souls). with the npc's I ended up throwing down we had a system of three main "towns" that constantly push the gangs against one another to slowly reclaim sections of the city or find good junk to use against other aggressor holdfasts and to use as protective screens.

The leadership of the big towns really reflect the top 5% ruling the 95% of the underlings, who for the most part are indentured serfs. The big towns generally didn't have any teeth either, so the interplay between the gangs the pc's were part of really got alot of traction in the game.

The small hubs that are gang protected run 30 to 60 people, the 3 or 4 main burroughs hold anywhere from 300 to 1000 citizens. Overall if we added up the forty or fifty gangs that dot the land the population is still extremely high, but isolated from each other, usually takes a few hours to get anywhere because of the fallout, rubble, enemy gangs, and mutated giant pigeons (or random evil robot.

Anyhow, that was the last game I ran, it was a pretty cool mix of Escape from New York, Banana Fish, and The Warriors.