The River Crag has maybe the best climbing at the lake. It's almost always quiet and peaceful, the rock is good and its a wide, low slung crag with a high concentration of routes in a relatively small area. Nice combination of crack climbs, face climbs, roofs, traverses and aretes. Since there's often a current here, it's recommended not to anchor your craft somewhere nearby and swim-in, instead just keep someone aboard to man the boat and keep a lookout while the others climb.
This is a really cool area and Cottonwood Creek Beach is just a 1/3 mile away when you want to take a break and land somewhere.