Note: We completed this route in 1986, making California Peak one of our earliest 13ers. Since our information is rather dated, we suggest checking other sources.
The Huefano Trail west branch heads uphill through fairly dense aspen, making a few switchbacks. It then comes out onto an open meadow at about 10,750 feet elevation. There are several reports of people losing the trail and we think this meadow may be where things go wrong because on GE, the trail fades here. Once the trail enters the meadow, it heads southwest for some distance, then re-enters trees at approximately these coordinates determined from GE: N 37° 38' 23.81" W 105° 28' 39.33". Once it re-enters the trees, the trail swings back north and makes a long NNW ascent to the ridge above. It comes out near the ridge crest here: N 37° 38' 47.28" W 105° 29' 11.37", at 11,840 ft. elevation. Once you gain the ridge, turn south for the long, mostly tundra walk over multiple humps (at least 5) to the summit. Of the four 14ers in this area, the California summit has the best view of Lindsey.
For the descent, to make things more interesting, you can continue south along the summit ridge until the south and east ridge intersect. Follow the more defined east ridge down to about 13,100 feet and look for a descent route into the basin on the south side of the ridge. There are multiple chutes with rock outcrops in between to choose from. This is where you'll get into some loose talus and scree, but the drop goes quickly into the basin below. From above, you'll clearly see this basin below has a number of rock-glaciers on the south side of the basin with a nice tundra swath that descends to Lost Lake. Follow the path of least resistance to the lake. This makes a nice, isolated place to take a lunch break and cool your feet. From the lake, continue hiking downhill to the NE on steeper terrain, then veer more easterly to avoid getting onto the great rock glacier that descends off the California east face. There's a minor creek drainage coming from Lost Lake that can serve as a guide, and north of the creek, but still south of the rock glacier, are some swaths through the trees that will lead almost all the way down to the road to help minimize any bushwhacking. You should come out close to the south end of the large meadow that is encountered early on when hiking the Lily Lake Trail. Once on the trail, then road-hike north back to your vehicle.
For an interesting and useful report that describes doing Lily Lake, UN 13,577 and California in reverse of how we describe, soo the report by "Greenhouseguy" on 14ers.com.
Links to other information, routes & trip reports for this peak that may be helpful.