Type: Backcountry or Sidecountry
Need to Know
Make sure to purchase a daily ($5) or Annual Sno-Park Pass ($25 CA, OR, and ID Sno-park passes all work). Park east of the Boreal Motel or you can get towed. Parking at the trailhead is highly dependent on snow levels and snow removal work. Better to not chance it and take the extra couple hundred yard hike to the sno-park area, if the lower gate (right at the exit) isn't open.
The Castle Peak/Andesite Peak saddle is the main jumping off point for objectives in the Castle Peak area. You get a good view of Andesite, Basin, and Castle Peak and their adjoining ridge lines and bowls. It's a good area to explore when the avy danger is highly aspect dependent, since you can access so many different aspects of differing difficulties intermediate and above.
This is an easy approach that is pretty mellow and mindless for 95% of it. The last little increase in grade usually has a straight up (STFU) skin track put in, and has been marked as such. But really it's worth putting in your own kick turns or follow the natural grade of the slope a bit more.
Some people will take that first fork to the right (when you come to a meadow) that connects you to the PCT, I would not recommend if you are trying to get to the saddle. It's much harder route finding, stream crossing, and undulating terrain at southern toe of the Castle Peak slope/PCT. It makes sense if you are going to the eastern flank of Castle Peak, but not to the saddle.
This is a trailhead for snowmobiles that are allowed west of Andesite Peak, east and north of Castle Peak. You'll only share the same trail for a few hundred feet. This path also because of it's easy accessibility is shared with many people snowshoeing, snow hiking, and hiking up to sled. So don't expect a nice manicured skin track.
Landmarks at the Saddle:
NNW is the Peter Grub Hut (managed by the Sierra Club), it can't be seen from the saddle because of trees
N is Round Valley and Basin Peak
NE is Castle Peak and its ridge line
SSW is Andesite peak