I hiked the Baldy Notch/Devil's Backbone Trail from Manker Flat on July 13, starting in the early afternoon, and returning after dark. Here are my trail observations, also posted to the trail description....
The trail is almost completely unmarked, except by heavy use, so first-time visitors should have a detailed map -- or at least study one at the Visitor Center.
The trail starts near two porta-potties at a dirt road junction at Manker Flat. This a broad area is just after the Manker Flat Campground. In season, there may be many cars parked here, but there is ample parking spaces along the side of the road.
If you drive the paved road beyond Manker Flat for about a mile, the road ends at the base of the ski lifts. Some people choose to start hiking from here and hike straight up beneath the ski lifts, but this trail is unnecessarily steep and loose, and signs warn that the parking lot gate is locked at 6:30pm. It is much easier to return to Manker Flat, even though you lose some altitude.
On the dirt access road from Manker Flat (Falls Road), the route is gentle and unambiguious. It follows the access road for about 2 miles to the group of buildings at the top of the first ski lift. Stay on the access road until you reach a four-way junction; then look up the road to the left and you'll see the ski lodge. Once you reach the lodge, there appear to be several possible routes to the west. For the easiest route, follow the access road leading toward the top of the left-side ski lifts. Judging from trail wear, most people go straight up a steeper ski slope. The gentler access road is to the left of this trail, and it snakes up the ridge rather than going straight up.
Once you reach the top of the 2nd ski lift, the trail gets more interesting. It follows the edge of a narrow ridge (the Devil's Backbone) and then snakes along the edge of some steep slopes. There is no serious danger during the day in the summer, but the trail could be difficult at night or in snow.
Befitting its "Old Baldy" name, the summit is a bare dome covered with rocks and gravel. At the summit are several crude rock windbreaks. These are horseshoe-shaped piles of stone that are just high enough (2-3 feet) to protect campers from the wind. Perhaps 15 people can sleep here. There is another similar windbreak in a much more protected location along the trail below the summit.