all good info here. If I could add something it would be a reminder about the ego. My first event I thought I had it pretty well checked. In retrospect, I didn't. No matter how good you are at Gran Turismo or how quick you are at the local indoor karting place, you're a total noob in comparison to the instructor corps. The first few events are about learning what you don't know.
Also, one of my big challenges is composure and attitude. Although its nice to have a hot coffee on the chilly morning, I find that it gets me too amped up. I'm so excited to be on track I can't calm myself enough to get in the groove untill after lunch time. Next time I'm gonna see if I can deal without coffee.
Personally, I will never recommend a first timer go to an event that isn't a BMWCCA or similar event. I've done it the other way and it was a waste. I see people cry about the BMWCCA events cost too much. In reality, it's only $100 more. The difference is, the cheap track time includes no instruction. (Lets not even open the safety can of worms.) The value of the instruction you receive at a BMWCCA event is far greater than 100. But, that's something you won't realize if you can't check the ego at the door.