ApproachStone Mountain, NC, is an amazing place and a wonderful climbing venue. Unfortunately, the two classic moderate climbs (Great Arch and No Alternative) don't start from ground level. Indeed many of the classic climbs in the center of the face start from the Tree Ledge one pitch off the deck. Getting there is the first part of the climb or the last part of the approach depending how you look at it.
There are two easy ways of getting to the Tree Ledge. The Entrance Crack is rated at 5.4 and is seemingly much easier than U-Slots. However, looks can be deceiving. U-Slots has one crux move at 5.7 with the rest being casual slab climbing of low grade. Entrance Crack is a sustained offwidth with no protection unless you've lugged along a supply of big-bros and massive cams. U-Slots is the easier alternative except for the one crux move.
To approach U-Slots, walk through the historical park and meadow and approach the middle of the rock by the standard trail. Turn left and fight your way up through brush and talus to the extreme left edge of exposed rock at ground level.
Route DescriptionU-Slots is a one-and-a-half pitch climb unless you have a very long rope. The first pitch is the short one and leads up about 50' across a shallow drainage channel to a bolt. Consider this your warm-up for the slab climbing to come.
P2: From the bolt, follow a shallow seam up and slightly left. You may find some marginal pro in the seam or just run it out. Before long, your upward progress will be blocked by a 5' high roof. Work your way along this to the right for 25'. In the spring, there may be wet patches on the rock which will require some resolve and finesse to cross. Adequate protection is available in the crack at the junction of the face and roof (a #2 Camalot fits nicely).
Just when traversing is getting old, you come the the signature U-Slot where a drainage channel has carved the roof down to a more manageable height. This is the crux. Place gear at your feet, reach up and pull the roof with confidence and aplomb.
Above the U-Slot, you're back on friction slab. Continue up and right over easier ground to the Tree Ledge (pictured at right). Directly above you is the fabulous Great Arch.
Descent: Presumably you climbed up here for a reason, right? Climb Great Arch or another classic climb to the summit and descend via the west side hiking trail. If you really need to bail from the ledge, a double-rope rappel may get you to ground level. I don't actually know.