HH Disney has several slips available in the marina for members and /or their guests. These slips are available free of charge.
A few years ago DBF was sailing the coast and met me at Hilton Head. I can't remember if I made the marina reservation through member services or through the resort itself, but there was information in the guide books somewhere that gave details. I think it wouldn't hurt to call the resort itself for information.
While we were at the resort, DBF did not use his boat, just left it in the slip, so I can't speak to boating in the area.
Hope this helps.
MJ