I went last year.
1.) Bring baby powder.
Edit: Any specific questions? I found the website to be mostly good at preparing me for the trip, but forgetting baby powder honestly was the worst mistake I made that week. Of course, that week happened to be constant 100 degree heat, so we probably got particularly unlucky, but I still have nightmares about that chafing. Otherwise: have a blast, and take advantage of the fountain in Centeroo.
I found a couple kind of survival guide kind of things. I'm mostly concerned about what time I should try to get there Thursday to not sit in traffic forever and also how much space I'll get to camp. We have 4 people in a jeep right now and are wondering whether we should bite the gas bullet and take another car just for the extra camp space