Are you going for the entire 4 days? Have you signed up for any games run by your fellow EN Worlders? Are you planning to attend the ENnies ceremony? I recommend you stop by the EN World booth and sign up for a few pick-up games. Many of them are full by now, but I know there are a few still open. Do that first, then build your schedule around that.
Save time for the dealer room. Bring cash, because you *will* want to buy things, and some of the smaller vendors don't take plastic.