I still not 100% sure of the ins and outs of cross realm zones.
I know Pandaria and Stormwind are not affected but I've been to Dalaran, Goldshire, Ironforge and most other Eastern Kingdoms zones and see people from DMF and SWC all the time. Just before MOP hit Dalaran was very busy again.
In theory therefore we should be able to join this parrrrrrtay in Westfall - I can't remember if the tower is affected by phasing though.
I put it on the calendar early so people can plan outfits and such.
If anyone knows better, please let me know!