You should call Chuck Bargeron. In addition to being the head of the Tybee Island Sailing Association, and organizer of the Tybee 500 - he's the City Marshall for the town of Tybee Island so he's more than up-to-speed on the regulations of keeping your boat on the beach. His number is on the contact page of the Tybee500.com site. It might be in the SI's. Hell its somewhere on that site

Here's whats going to be your problem though. Are you planning on bringing your cat trax with you across the river? Its a long haul on the sand past the tide line.