Artemis climbs to the top of the obvious dihedral high on the left side of the wall. I thought that the 5.9+ pitch, although quite good, was no gimmie.
Pitch-by-Pitch Photos
Approach
3rd
Begin about 100 feet right of the low point and scramble up and right along a ramp to the base of the route.
Pitch 1
5.6, 100-150'
Work up flakes to a right-angling ramp that leads to a large flake. A bit of your choose your own adventure pitch.
Pitch 2
5.4, 100-150'
Head up and right from the flake. Traverse a narrow, rising ledge to its right side and belay at the start of a huge, hanging, left-facing dihedral.
Pitch 3
5.9+, 80'
Lieback a crack to an overhang and pull through on the left. Go past a ledge to a second one that's just right of a big roof. Although the climbing was good, I found the rock on this pitch to be a bit flakey and the climbing to feel a bit insecure; it got to my head a bit and I struggled more than I would have liked on my lead.
Pitch 4
5.7, 80'
Climb the dihedral to the ridge crest.
Top
12,660 ft
The route ends much closer to the beginning of the rappels than the summit, so if you've already tagged the summit before, it may be tempting to just start the descent.
(No photos. See photos for other ascents of Arrowhead.)
Descent
Rappel
Scramble down to the low point between Arrowhead and McHenry's Peak, which is very close to where Artemis tops out. Locate the first rap station (under a big boulder). There are two raps and some 4th-low 5th class downclimbing. A single 70 works just fine.