When you have a chapter specific question, your best bet is to go to that chapter's forum on this board and ask the question in the OOG section there. I believe Seattle's is under their "Members Forum" .
All Alliance home games (there are some special events) take place on the world of Fortannis (to the best of my knowledge) and each chapter/campaign takes place somewhere on that planet. Again, to the best of my knowledge, there is no map that outlines exactly where each land is located. A long time ago, they attempted to mirror the US a bit in the land masses but as so many chapters have gone through land changes (I believe that since 1994, there's been a total of 8 different locations/lands/countries in the San Francisco chapters alone) I don't think it's feasible. But I could be wrong.