Make sure you have mostly black clothing, preferably without obvious markings/pictures/logos on them. Your best bet is probably black sweat pants, but if you really have to, black jeans. Avoid blue jeans and white shoes. You'll be much better off with boots or dark colored shoes. Make sure you have a pillow, toiletries, extra socks, a towel if you plan on hitting the shower, and something you can layer on (something with long sleeves is good to have, it'll get cold at night). Also, bring some extra socks.
We'll provide costuming, but if you have some of your own that you're comfortable in, bring it along. We also supply weapons, props, makeup, masks, and meals for Saturday Morning, Saturday Night, and Sunday Morning. I'll get back to everyone on Friday Night food, don't count on it yet. There will probably be 'grab and go' lunch as well, but plan on having your own snacks. We'll also have soda and bottled water on hand. You'll need to bring your own pair of extra socks.
It'll also probably help if you post where you'd need to be picked up from. We have people coming from 1000 miles away in several directions, that's a wide area to choose from.