ApproachGet to the Big Beaver Trailhead per instructions on the main page. There are two possible approaches from here. One is to go up Access Creek, possibly climbing Luna Peak along the way, then dropping down to a camp at Luna Lake. Drop a bit further to gain the buttress. The other (which I have done) is to follow the trail to Big Beaver Pass, then bushwhack up Wiley Ridge for a long day to reach the Challenger Glacier camps. You definitely should climb Challenger as a warm up, it is so easy from there! Drop down on snow, heather and ramps into Luna Cirque to make a camp below the imposing North Buttress. We took 3 days from the trailhead to get here, although a motivated party could do it in 2 full days from the trailhead (skip Challenger).
Getting onto the rock buttress is probably the crux. In earlier years, the glaciers below Swiss and Fury peaks were less broken, providing easy access from the right side. Kearney reported access from the left side required 5.8-5.9 thin climbing. We followed an obvious snow ramp on the right side of the buttress up to gain 5.5 slab climbing that led to another snow gully. This gully was climbed for 400 feet until we could trend back left on ramps, making for the buttress crest. Gaining the crest proper required a short pitch of 5.8 crack climbing with decent protection. Once on the crest we followed endless pitches of low fifth class, only occasionally setting a fixed belay. The upper third of the route is a straightforward snow fin which may be steep/icy enough near the end to require protection.
50 meter rope, medium rock rack, 1-2 ice screws, 2 pickets. Crampons, ice axe. We took rock shoes, and think they speeded our ascent of the buttress (allowed for more confident simul-climbing).