You get your own entrance and a better campsite for the price of the VIP tix. You also get a spot in the bleachers set up by the two main stages, so you don't have to sit on the ground in the crowd. They're not right up front, but the sight lines are at least decent. There's also a special VIP area, and last year a few of the bands played concerts in there - although I wouldn't set hopes on getting to see our guys there. (I'm still hoping against hope for a Ryman Auditorium date in Nashville...especially since I heard a rumor that Stewart's interested in bluegrass these days.
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You do camp next to your car, cp. I hear folks recommend you bring a camp shower, water canteens, etc., because allegedly the shower facilities are pretty primitive. I'm a camper myself and would do it in a heartbeat were it not for the fact that I'm also an insanely light sleeper and I understand people have a tendency to party all night at this thing.
You can also get yourself an RV pass, seems like the cost last year was around 50 bucks. I've often considered the RV-rental route for this thing. There aren't any water or electricity hookups, but at least you'd have privacy, less noise and doors you could lock.
I suspect A LOT of people will come this year because the word is getting out on the rapid sellout of Police tix in other venues. Also, getting here is relatively easy, since TN is centrally located and Southwest Airlines flies to Nashville. So be ready to buy those tix the minute they go on sale if you're even considering coming. You can always unload them later on Ebay if you wind up having to change your plans.