From the Fourth of July trailhead on the north side of the parking lot, follow the signs for the Arapaho Pass trail Photo #1 to start. The trail starts out with a gentle climb Photo #2. There are plenty of social trails, side trails, and closed-for-rehabilitation previous trails, so stick with the clear and heavily trodden trail when in doubt. The trail climbs about 500 vertical feet in easy class 2 terrain Photo #3 in the first mile. Step carefully over various small streams.
Around 1.1 miles at 10,750 feet you reach the junction of the Diamond Lake trail. Stick with the Arapaho Pass trail Photo #4.
At 1.5 miles, around 11,100 feet, the trail goes almost level for half a mile of beautiful scenery Photo #5. At 2.0 miles and 11,200 feet, you’ll reach the ruins of the old Fourth of July pit mine and the juncture of the Arapaho Glacier trail Photo #6, a much smaller trail than the Arapaho Pass trail. Take care to make this right hand turn onto Arapaho Glacier trail.
Within a few feet you’ll cross a substantial stream or marshy area Photo #7, pass a large boulder Photo #8 and then continue your ascent Photo #9 Photo #10 gradually gaining altitude. You’ll pass through 12,000 feet about 3 miles from the trailhead Photo #11. South Arapaho Peak’s summit comes into view to the northwest Photo #12 and Old Baldy’s summit comes into view to the northeast Photo #13.
To summit Old Baldy to the northeast, you can continue on the Arapaho Glacier trail Photo #14 to the saddle between Old Baldy and South Arapaho Peak and then go east off-trail to Old Baldy’s summit, or you can take a more direct line off-trail to Old Baldy’s visible summit Photo #15.
As you ascend Old Baldy, you can see the ridge up South Arapaho Peak to the west Photo #16. After achieving the summit of Old Baldy Photo #17, head west to the saddle between Old Baldy and South Arapaho Peak Photo #18.
Ascend between the cairn Photo #19 and the cliffs that drop onto the glacier. Follow the ridge line Photo #20 to the false summit. The terrain becomes more difficult here Photo #21 and to keep it as class 2, you’ll have to pick your route carefully. Comfort with a few class 3 moves gives you some more flexibility in route over the rocky scramble.
The true summit becomes visible from the false summit Photo #22. Follow the ridge line to gain the true summit Photo #23 and locate the geo-marker.
The ridge line continues on the route to North Arapaho Peak, but the route becomes Class 3 and Class 4 rock from here.
On the return route, follow the ridge you ascended back to the saddle between South Arapaho Peak and Old Baldy. At the saddle you can rejoin the Arapaho Glacier trail heading southeast (not due east) and follow it back the way you came to the Arapaho Pass trail and finally the trailhead.