In the recent email it directs folks with Mary E camping and vehicle passes to the box office to get them scanned. I don’t remember this in past years and seems like a nightmare to be directed towards town and then back out.
If you have proof of confirmation of tickets/camping you can enter Illium, and wait till the shuttles start runniing to get to town and get wristbands etc… If arriving after wednesday you might hit Box Office first, it’s across from the Post Office, easy to find.