Cobal Canyon to Potato Mountain is one of the long ways to do Potato. It is also one of the most classic mountain bike rides in the San Gabriels. The only drawback to this route is the Claremont Wilderness Area is very prone to fire and flood closures and it is a gnarly summer/smog ride. In the spring there are trantulas on the roads and flowers on the hillsides. This peak can be combined with many other routes linking to Marshall Canyon, Claremont Wilderness, and Evey Canyon.
From the Wilderness Park trailhead go through the gate and head up the fireroad to the first junction. Take the right fork signed Cobal. Head up this road to another junction at a water tank. Go right at the water tank and continue to another fork. Stay to you left and continue and continue until a another fork at the saddle for Evey Canyon and Potato Mountain. Take the right fireroad up to the summit of Potato Mountain.
The round trip is about 9-10 miles with over 2000 feet of gain.
A fun side route from the summit of Potato is to take the open steep firebreak that descends to the northwest back down to Evey Saddle.
From the Baseline Exit on the 210 freeway head west towards Claremont. Go to the second lighted intersection at Mills Ave. Turn right onto Mills and head north towards the mountains with the towered summit of Sunset plainly seen. Go all the way to the Baldy Road junction. Go straight, on your immediate right there is the Wilderness Park overflow parking, continue straight to the upper parking lot and trailhead.