First I'd check all the info/pages (especially the "camping" page) on this site: http://www.southcarolinaparks.com/hu...roduction.aspx
If you click on the "Park Reservations" graphic on the right under the map, it'll allow you check site availability for the dates you're interested in, reserve sites, see campground map w/ site details, etc. I believe I had site 38 which is an oceanfront site for tents or hammocks only...it only has water, no electricity. There is a couple hammock setup options available on site 38 (in other words, more than one place to hang a hammock)...other sites have multiple options...some sites have none, though there is a surprising number of trees in this campground for it being a beach, etc.
One way I help determine which sites are suitable for hanging is to use the pictures on this website: http://www.campsitephotos.com/campgr...and-State-Park
There are pictures of most of the sites...though some of the oceanfront hammock/tent sites are not included...including site 38 that I stayed at last fall.
Hope this helps! I can't wait for an opportunity to go hang at Hunting Island again...I greatly enjoyed my hang time there!