If you're willing to swap brake pads, I'd just get a cheap set of the EBC yellows. They'll take the punishment at the track and save you from demolishing the OEM pads that will rapidly wear (or worse, chew up your rotors when they overheat). Just remember that even if you bed in the yellows before the event, they're still going to take a session or two before they're really working well.
If the tires are nearing their end-of-life... make sure to check them after each session. And you'll probably want a contingency plan (i.e. some spares) to get you home if you cord one. I find a lot of the time you *think* you've got a track day left in the tires, only to find out you're corded right on the edge of the tire after just one session.
Factory safety gear should be plenty in addition to your helmet. I'm not sure about dress-code, but wearing long pants and long sleeves (all cotton) is the next best thing to a firesuit. Good sneakers are a must.
There are tons of great tips from Van's thread over at RenoSCCA:
http://www.renoscca.org/forums/showthread.php?t=890