I now find myself with a garage full of more wheels/tires than I've owned in my entire life.
Just a garage full huh? Rookie. My wife always asks since when did our basement become a second garage?

Have you done any HPDEs yet? If not, do some before the school to gain experience (and shake the car down as previously said). In regards to crew, bring anyone that's willing to go. They don't have to even know how to work on cars although that would be helpful. Even bring your wife. There are a lot of simple things that you just won't have time to deal with such as putting fuel in the car, checking tire pressures, washing the windshield, and so on.

The other advice I'd give you is get your wife involved in this obsession, I mean hobby. Does she like racing? Bonus if she does! If not, take some time to figure out things about the weekend she could enjoy. Get her in the garage with you from time to time even if that means she's just reading a book while you're out there. My wife hates getting her hands dirty (with car related stuff) but has saved my butt several times. Anytime she hears "wack! wack!" she runs out, tells me to put the hammer down, then somehow just gently resolves the issue. Gesh, that pisses me off! LOL My wife was not thrilled about the whole racing thing but I finally learned ways to make her like it more. It sure does make things easier for both of us.

Best of luck!