The easiest approach to Tinkham Peak is via the Mirror Lake Trail #1302. This trail is about 1 mile in length and gains only about 600 feet. It’s typically in good shape with minimal rocks and roots to contend with.
Cottonwood Lake and several campsites are passed about a half-mile in. The trail then continues up with a couple of switchbacks through the woods and meets up with Mirror Lake and the PCT. More campsites are located in this area. From here, Tinkham Peak can be reached by going either direction on the PCT. The southeast spur starts at the south end of Mirror Lake and the northwest ridge will be north on the PCT about another mile.
Travel north from Mirror Lake almost 1 mile, gaining only 200 feet or so, and then ascend a rockslide on the left-hand side of the trail. Continue up the rockslide to the ridge at about 4,700 feet. From here a faint trail can be picked up as it enters the wooded ridgeline. After several hundred feet, some of it pretty steep, the climbers trail exits the trees and finishes on open slope. A couple of easy class 2 moves and the summit is gained.
No technical gear is needed during the regular climbing months.