I'd say logon and ask people there seem to be a healthy horde pop on both NA and EU times, usually more alliance but surprisingly balanced, I'd just join and see what guilds are forming it's still early and I'm not sure everyone has coalesced into guilds just yet, for example with /who I could see horde players running wailing caverns at both 10pm est and 10 am est so I think you'll be fine just playing the faction you want and trying to meet people.