Think camping in Jurassic Park.
The under (and over) growth is incredible, and makes for wonderfully private sites.
Of course, backing your rig into some of the sites is not for the faint of heart. Knowing your height clearance, and/or having a spotter is highly recommended.
Beautiful state park. The only option if you want to camp with direct beach access (except for that sorry dump called Bryn Mawr). Plus, historic old St. Augustine is only minutes away.