Just a thought, with the story starting in downtown will there be any areas that for whatever reason be inaccessable at the beginning, be it over-run with zombies, npc survivors like bandits etc?
The entire downtown. When you take half a million zombies, stuff 'em into a congested square mile and add a couple of thousand panicky survivors... Nothing's going to be accessible. I'm planning on having the game open with everybody in one location after they fled their original hideouts due to events that will be detailed in the opening post. I'll leave a couple of story hooks, but from that point on, you're on your own.
I was thinking maybe the local hospital and the grocery store since food and medical supplies will be needed at some point.
Hospitals, grocery stores, gun shops, car lots, and shopping malls will be the first places to go as everyone rushes for supplies and vehicles. Either some wannabe warlord will start a firefight and lay claim to it as her own, or the zombies will swarm the place and turn it into a deathtrap. Since it's Boston, most thoroughfares will be off limits for anyone cares about their own survival, and tunnels -- long, confined, pitch black -- are natural death traps. You'll have to get creative if you want out of the city.
That's my take on it.
I plan on Usani and I having a proper intro post up within a few hours.