Since I had to be careful to avoid crevasses going by myself, I took essentially the Hyas Creek Glacier Headwall route. I departed from the trailhead at 6:20 AM.
On the way up, from the Hyas Creek I deviated to the right, scrambling up to and along the ridge east of the East Spire. At the spire I considered taking the northern route via the top fringe of the Lynch Glacier, but decided against it because it was too steep (and the snow still not soft enough) to walk without crampons. So I turned left instead, following the bergschrund, and then scrambled the East Peak. Descending from there directly to the Middle Peak (with a short section of about grade 5.3 ending in a gully) was very ugly because of extremely fragile rock - even bigger pieces crumbled or moved when merely touching them. I had better taken the path down to the South. I quickly visited the Middle Peak before reaching the true summit (West Peak) at 12:50. On the way back starting at 1:20, the horizontal traverse in the south of East Peak is in part very slippery. Glissading down Hyas Glacier, including some 3rd class scrambling in the middle, was fun though. The final section of the trail down from Cathedral Rock is very gradual - which is the case for many approaches in the Cascades, making them suitable for trekkers, families and stock, but not so much for mountaineers who would like to gain (or reduce, respectively) elevation quickly. Not rushing neither up nor down, I was back at the car at 6 PM.