I personally love Uwharrie National Forest for riding. We stay at Canebrake Horse Camp. There are no beaches, but there is a lake. The trails are all marked with paint and color coded. The trail ranges from easy to extremely hard. Even on the easiest of the trails, though, your horse needs to be trail ready. Even the easy trails are to much for a horse that is only rode in the arena a couple of days a week (not saying that's what you do). So for a summary...
It is physically demanding for you and your horse
You can't ride side by side...the trails are narrow
The trails are well marked
It is quiet and peaceful riding
There are places where you can water your horses
You can get in the lake and swim with your horse Uwharrie National Forest - Canebrake Horse Camp