Find the lighthouse. Beacon Point, as I recall. It's just past Cobb Inlet, right near the large island. Southwest area of the lake. When water is up near normal, this is about as "beach" as it gets. It's rocky on the point and further out, but typical swimming area is pretty good. It can be busy, though! I believe you have to pay a few bucks, but I had a lake house just around the bend so I never had to pay when I anchored up there.