I am unfamiliar with the Rio layout since I typically goes else where in Vegas but google maps has a nice layout:

http://www.riolasvegas.com/rio-las-v...l#.VBnTVUg_3z0
(I’m guessing FFXIV will be taking up the back in the Pavilion and/or Amazon Rooms.)

It looks like Hyperion has a pretty good chunk of people going so staying close or within Rio might be best for a meet up? Perhaps meet up after the Fair hours?

Maybe the Masquerade Bar? They’re open 24hrs according to google. There is also TGIF across the street.