I was thinking of making a Fallout game, but didn't give much interest to me so I decided to go back to another post-apoc series I've always liked, and I think an ATF in Seattle would be a great setting. I believe Seattle could've taken part in the supply lines between the Post-war US and Canada (as mentioned in the Radio on ATF: Rain) and considering it to be a coastal city with a large harbor I would really see it having an abundance of pre-war weapons making it a civilized place whether the right people got a hold of it or not.
If it wasn't obliterated by the hellfire from the nuclear war, it could most likely hold a lot of ACMF Remnants and can also have a wide variety of different enviroments including downtown areas, harbors and pine forests. It might even be a good place for our characters from Pearl Harbor to continue their stories. If you guys have any input on this subject please comment, I'd like to see what you guys think about this.