From the Town of Gunnison: Turn north at the center of town on HWY 135. Pass through Almont and continue toward Crested Butte. About 2 miles before reaching the town, turn right onto CR738 which also becomes FR738. This is locally known as the "Pearl Pass Road." The road starts out paved, then changes to graded gravel. It initially passes through a subdivision. Before turning off the highway, you'll have outstanding views of Teocalli Mtn. Passenger cars can make it in the first 4 - 5 miles to a little past the junction where the East River comes in. Just before FR 738 begins to gain elevation, and shortly after FR738.2A turns off for West Brush Creek, there is a primitive camp area on the right. Passenger cars should be parked here. If not parking a passenger car, turn left onto FR738.2A which heads NE on higher slopes above West Brush Creek. The road turns a more northerly direction after about half a mile and then stays well above West Brush Creek for the next mile and a half before dropping down to and crossing the creek. There is a good campsite here.
Continue on the east side of the creek now for another 2.2 miles appx. to the end of the road. There is no formal parking area - just a grassy, open knoll after climbing steeply up a section of road that passes through willows. This last two miles will be the slowest mainly because of potholes. We did not find too many rocky obstacles on a drive up here in 2011, but some minor drainage crossings proved to offer some clearance problems. Much of the 4 mile drive in passes through open, grassy terrain.
It should be noted that this trailhead can also serve as a TH for Teocalli. A trail which does not show on either the USGS quad, or the Guinnison NF map, heads east from the parking area to the south ridge of Teocalli ("Teocalli Ridge" on the USGS map) and crosses the ridge at 11,100 ft. Head north from that saddle for an easy Class 2 hike to the summit on a trail that eventually fades away below some minor cliff bands.
From the trailhead, a trail leads north to NW on the east side of the creek for about ½ mile before it begins to fade. Before entering a forested area, cross the creek where the trail comes very near to it and head up an open slope, not too steep, staying near the edge of the forest. After about 400 feet of gain, head into the forest and work your way through the forest into the upper basin of West Brush Creek. You may at times see something of a trail in here. Pass along the foot of a rock glacier where more trail may be evident and eventually intersect the creek and continue along the drainage, to the end of the trees, hopefully finding a trail again that also heads NW to a saddle between White BM and a minor 12er of 12,728 to the south of White. (Note: if you want to include White BM on this trip, you can follow this trail to the south ridge of White BM and then walk north along that ridge to obtain that summit.) About the time you spot this trail, you should turn off it and head NNW into the basin SSE of the White Rock Mountain summit. If you stay on the east side of the drainage that empties the upper basin, you'll surmount three benches with tundra, low evergreens and some willows. The final bench deposits you below the SE face of White Rock. At about 12,600 feet, there's an inviting, beautiful, grassy area with a small stream flowing through that's frequented by elk.
Now the real work begins. Begin hiking NNW, heading for a flat saddle on the east side of what appears to be the summit. This will entail 600 feet of gain on unstable rock. Once on the saddle, hike easily west until you come to the final 100 yard stretch to the true summit. Though the summit appears near, this last 100 yards can take up to an hour if you choose the wrong approach. This last stretch of mountain is comprised of a whitish-colored rock of little solidarity. It has eroded into pinnacles and steep gullies filled with very loose sand on the south side of the main ridge. If you choose to stay on this south side, navigating a path across these gullies will be the challenge. A better, easier and quicker route follows the ridge crest a very short distance until you're forced off of it onto the north facing slopes below the crags and pinnacles. Contour as best you can, perhaps losing a little elevation until you work your way past all the difficulties and are below the true summit. Then, scramble up a short but steep gully, filled with loose rock ready to break off and plummet away. The head of that gully brings you out on the summit. Wipe off the sweat, steady the nerves now and try to enjoy the expansive view of the southern Elk Mountains.
Return by the same route. Some may wish to consider a trek over to White BM along the connecting ridge. Not recommended if you like easy-living because of major difficulties, but who are we to tell you not to try?
White Rock Mtn. can also be climbed from a high camp in the tundra south of Coffeepot Pass. Here's a brief description of how that route would go: From a camp at about 12,400 feet, head SW across tundra, contouring for the first half mile and then beginning to gain elevation as you head for a break in the ESE ridge that comes off point 13,318. Clamber over rock to the break in the ridge. The last 100 feet is the most difficult. Descend on the other side for 600 vertical feet to a small, unnamed lake at 12,600 ft. the descent will take you over very loose, unstable and large boulder talus. From the lake, lose more elevation to a little below 12,400 ft. to contour around yet another ridge and below cliffs. This will entail yet more boulder talus. Once around the ridge, head WNW into the basin SE of the White Rock summit. From here, follow the directions above for the climb up the SE face.