IT's been my experience that if you have a national event on the west coast, you'll get nothing but west-coast people. If you have it in the middle of the country, no one but locals will come. But if you have it on the east coast, you'll get people from all over. It works that way because the east coast is more densely populated, so you'll get a lot more people just because it's closer to them. Then people from the west coast will see how big it's getting and want to get in on it too. If you hold something on the west coast, or especially in the middle of the country, there aren't enough "local" people to make it big enough to interest people from the east to come.
I'm really excited about this possibility. I've thought about trying to set something up before, but never really got anywhere.