Hike to the Marsupials as described on the main page. Head for Koala Rock. At the lowest point of Koala Rock there is a large boulder. Just to the left of this boulder is a thin lightning bolt crack, that becomes straighter and wider as the angle eases.
Begin in the lightning bolt crack, two or more easier moves lead to the strenous 5.9 moves. The crack is too thin for all but the smallest fingers, so thin face moves pull you through. After this section, the climbing eases to 5.8 and 5.7 finger jams, followed by hand jams with great knobs sprinkled all over the face. A second pitch of 5.6 knob pulling with crack for protection can be done, but the first pitch is why people climb this route.
rpc adds the following on the next two pitches:
Pitch 2: 5.8-5.10a bolts. The pitch opens up with the crux boulder move. It's highly reach-dependent. Ryan Lawson's book rates this 10a. That's probably an overestimate. If you're somewhat tall (or skilled), this should not feel harder than a 5.8. Belay on a small ledge with two new bolts.
Pitch 3: 5.10a, bolts. The opening move is the crux of the route. Pull a short but steep bulge. Look for a three finger pocket left of and above double bolt anchor. Once past this move, climbing eases to a 5.7 face. Belay 30 feet below the summit from two bolts. (nice big ledge).
1. Rap the route, back to the top of P2, then left off bolts on top of a different sport route. Probably only need a single rope.
2. Top out the route with 3\4 class scrambling. From the Koala summit, downclimb to a sandy alcove and look for rap bolts atop a hump in the rear of Koala Rock. Single rope brings you to the ground.
Smallest stopper needed is a #6. Largest piece used is a #2 Camalot. Small to medium stoppers or tiny cams protect the crux. Many Smith climbers swear by the Aliens brand of cams for the tuff of Smith rock, so bring 'em if you got 'em. Second pitch takes larger gear, up to #3 Camalot. Leave the hexes in the car.
Further to the left of Thin Air are some easy and fun 5.7 bolted sport climbs, and just left of that, is Round River. To the right, around the toe of the buttress and uphill, are some more exciting climbs, see description for Ryan Arete.