Buttercup said:Good advice.
Also, many of the vendors accept only cash, so your credit card will not be all that useful (except for the hotel and meals, of course).
Food at the convention center is really expensive, and pretty lousy. However, there's a Subway in the basement of the Hyatt, which is a short skybridge walk away.
I'd suggest that you not overbook yourself. My first year I missed out on some games with EN World people because I had signed up for too many events. Last year I signed up for fewer, but two of them the presenter never showed. This year I'm not going to bother. I'll be able to keep myself busy with pickup games, I'm sure.
Second this.
See Buttercup's sig - Volunteer for the EN.World booth, if not just stop by and meet the people there.