Most of us are arriving at the grounds by 8am to give us plenty of time to unload the cars (coolers, chairs, etc) and then get them shined up. Some people get there at the crack of dawn!
I dunno that you actually get an assigned SPOT as much as an assigned AREA, but it's not like you'll get there and have nowhere to park. There are attendants all over the place who will guide you to your designated area. As far as where the tent is, no one will know until we get there. If I have time I'll scope it out Thursday night and post it on the forums for anyone who can read them from the hotel.
All that being said, Carlisle is easy to get around and newcomers have nothing to worry about as far as finding their way around. I actually spend a lot of time at the tent as this is basically my annual vacation (and don't forget free lunch on Saturday starting at noon!) So feel free to stop by, take a seat, rest up a bit, and socialize!
Crap I just thought about it - without 4C there I might have to supply the toons at the tent...
ViperMan