The Dan River Co. can give you a shuttle up river but you should make an appointment as they tend to get busy on the weekends.
I'm not sure what the status of the campground is. They've opened and closed so many times I can't keep count. You may want to post a message to http://www.facebook.com/HangingRockNc?fref=ts and see what they know. The last time I stayed there was when it was privately owned, many years ago. It was clean and quiet.