As one of the host who joined Stik a couple of years ago, I concur with everything he said.
I'd also add that the pit pass is essential as there's bugger-all else to do there if you aren't in the pits between races.
I was most impressed by the openness of the competitors. There were no drapes of secrecy hiding their modifications or anything like that. Everyone (and I mean everyone) I talked to would go on at length about what they had done to make their airplane faster, how they flew their race, etc. The guys from Nemesis even showed us some of the very-impressive telemetry that they use to get more grunt out of the engine. That bit, talking to the racers and mechanics in the pits, was what really made the week worthwhile for me.
As for parking, don't bother. Courtesy buses run from the hotels and turned out to be much better than driving ourselves.
On the casino front, the Peppermill is interesting, to say the least, and possibly unique in Reno for it's decor (but may not be to your liking if you're not into blue and green neon).
Have a great trip!