This is the latest information I have that addresses the above questions. I emailed and asked if the email notice I received constituted an invitation, and received this email.
"Stanton,
I’ll leave your name at the front gate. Hope you enjoy the Expo!
Best,
Chad McClure
(843)846-3180
www.braysisland.com "
I will assume from this that, if you desire an invitation, email or call the above number. It's worth the effort, IMO.