Maybe not the hardest, but likely the most sustained hard friction of the Tree Ledge approach routes; this one pretty much never lets up. One assumes the 5.8 rating in the "Selected Climbs" guidebook is a misprint.
Start at a short diagonal crack (or if you're up for it, make a direct start right of the crack). Follow the crack up and right, then straight up with delicate moves to the top. Can be toproped from the anchors with two ropes.
Starts just left of the Entrance Crack, near the right end of the Tree Ledge.
I climbed with the FA party a couple times. He told me stories about this route and how he had to hand drill one of the bolts with a broken bit while standing there on the slab. He claimed that it was so stressful on his calves that he acquired a varicose vein in one leg from that ascent. Haven't seen Paul out in a long time.
I think 5.8 maybe 5.8+ is right on for this climb. It does not, however, really have a crux and never really lets up. Unlike many other Stone Mtn routes, it continues at the same difficulty whether by a bolt or far run-out, making it feel harder. From the last bolt to the anchors fells pretty far.