Climbed Northeast Ridge System from Twin Lakes. Started West of Tamarack Creek from South Twin Road. Class 2. Be prepared to do a lot of bushwhacking in thick shrub via this route.
Summit is part of ridge system/peaklets that run south toward Monument Ridge. Can be hard to tell where summit is. 1990 USGS topo lists high point at 11318. Found two places where someone had placed white PVC pipe for summit marker.
Possible to get onto class-3ish boulder field toward top of North East route.
Descended via gully directly above dam between Upper and Lower Twin Lakes. Class 2/3. Stay in easternmost gullies when descending this way or you could easily find yourself on loose/chossy class 4/5 terrain on North Face. Ascent could probably be made this way if you're up for a challenge.
Via Upper Summer Meadows.
I personally saw no craters on the summit ridge but there were great views of Twin Peaks, Matterhorn and the Sawtooths.
It was windy and cold.