Tso's got the right of this. As an old hat GM, I can say you definitely are not going to need more than a thread or two. Sign-ups, updates, and maps in an OOC thread, and the game thread. The pace will not be that manic, I assure you. Even at the most active, you'll have a couple dozen posts a day, and that's if you're quick on the GM and have motivated players.
Just organize your stuff clearly, and reading through it won't be a problem.