But first, note that this tour begins not at the Sno-Park near Boreal (see the start of the previous tour), but at the proper Donner Pass, on old US 40 just past Sugar Bowl and Donner Ski Ranch (I-80's pass is called Donner Summit). Why start the tour from a farther trailhead? Perhaps because the Castle Peak Sno-Park was full. But really because we need to fill a gap between the Mt. Lola Tour and Donner-to-Squaw, and because the lakes route from Donner Pass to Donner Summit is a pretty cool addition to the tour.

Anyway, you can usually park at Donner Pass just to the east of Donner Ski Ranch near ASI's Donner Spitze Hutte, along the road (not in the parking lots). There are two good routes to get from Donner Pass to the Boreal/ Castle Peak junction at I-80:

• The more scenic and interesting way is to swing east of Donner Ski Ranch to Lake Angela, then continue to contour northward to Flora and Azalea Lakes, and then curve westward to the Castle Peak junction SnoPark area near I-80
  
• The quicker route is to skirt around the right perimeter of Donner Ski Ranch to the first saddle, then continue straight, up to the right side of Boreal Ridge. Drop down to the base of Boreal via one of the resort routes
  

Once you get to the vicinity of the Castle Peak SnoPark and Boreal's parking area, walk across under I-80 to the Castle Peak trailhead (see the start of the previous tour).

Now what most people do from here to get to Castle Peak is to follow the Grubb Hut route to Andesite Ridge, and then ascend from there onto the west shoulder of Castle Peak. Then, within a few yards of Castle Peak's summit pinnacles, they say "nah" and ski back down.