I live in Cleveland, Oh, and up here there is a pretty loyal group of 7 or so players, including Stalker here on the forums, his brother, and we have brought couple of new players in over the last few months as well.
Our biggest obstacle up here is some of the local stores either refuse to carry the game, or allow us to play at their stores, but will not carry it unless we can guarantee a certain amount of sales per month, which is something that we cannot guarantee at all.
Back in my home state (Texas), the same thing occurs as well. I think that the game is big in some areas of the state, but there isn't a large, grassroots following down there yet.
I agree with dmcgee1, that the game will grow as people see the level of sportmanship and camaraderie amongst the players. I have the luxury here in Ohio of being less than 2 hours from one of the major game cons in the country (Origins), and less than 5 hours from another (GenCon Indy). I can't count the number of times that I have seen fistfights break out during some of the other game's tournaments (anyone that was at Origins 2 years ago might remember that one). It was reasons like that that I stopped playing some of those games in favor of something that, while not as popular right now, has a more friendly environment.
That isn't saying that there isn't anyone that plays Warzone that isn't a major pain (I played a game at Origins 2 years ago in which someone was thrown out of the game for being a real pain in the rear), but they are very much in the minority.
I think that you are doing the right thing, playing at a local store, and talking up the game to whoever asks about it. It's doing little things like that that will get the game to grow.
B.
okay...that was a little long-winded...