I've been 3 times, but I didn't go the last 2 years. We always end up going back and fourth through the infield between the 'esses' or right beside the infield tunnel. The best wrecks tend to be in the 'esses'. Wear comfortable shoes, bring sunscreen, light chairs, and a pop-up tent if you have one...and a cooler full of whatever. I have a big pop-up tent, and I'd be happy to share. I plan to do infield parking this year, that way I don't have to carry that big bastard very far. There's no Audi corral this year, which blows...I was hoping to park in some designated area like a corral. Not sure if the pop-up will fit in there anyway. If it rains, which I hope it doesn't, just bring a rain jacket. I was there for the race that ended early, and the rain was crazy, and it was cold as fuck.
Get there crazy early in the morning for good infield parking. Like before the sun starts to come up early. Walk all over the place...tons of great places to watch from. Outside of the back straight is usually empty and a great place to watch flat out speed.