I sent their customer support an email asking this question, and this was their response:
"Thank you for your inquiry. Yes there will be in and out privileges for the campground however due to the high volume of traffic times are allotted each day by management. Please check with a Live Nation employee before exiting the campgrounds."
Not entirely sure what they mean but that, but it looks like you'll be officially allowed to a certain extent
Yep, pretty much follows how they handled it last year as well. If there's a massive backup to get into the campground, don't even bother asking them about it. During periods with light traffic they probably won't give you any problems. Assume that there will be a period of heavy traffic from Thursday afternoon until at least early Friday afternoon, and plan accordingly by bringing enough supplies to last until traffic dies down.