The Mountaineer's Route is class 3. It was first ascended by John Muir in 1873, and for that reason alone deserves to be climbed. Follow the Whitney Trail for about a mile, leaving the trail after crossing the second creek (this is the North Fork of Lone Pine Creek). There is no maintained trail here, but there are vestiges of a use trail that is reputed to be difficult to follow. Stephen Porcella and Cameron Burns provide a good description is their book, Climbing California's Fourteeners, p. 66. Stay on the south side of the creek for the first mile or so until the canyon becomes chocked with Alder. Cross to the right (north) side of the creek and follow it up to Lower Boy Scout Lake. Pass the lake on the south side, climbing up to just south of Upper Boy Scout Lake. Look for class 2 passages up to the hanging valley to the south, and climb up the steep slopes here. Once in the valley, it curves the west, and the Whitney massif will become quite evident. Follow the easiest slopes west and northwest up to Iceberg Lake. The Mountaineers Route is the obvious couloir just north of Whitney's East Buttress. Follow this couloir up to the Sierra Crest, and then follow the ridge a short distance to the southeast to the summit. This route contains some considerable cross-country travel, and should not be undertaken as a dayhike unless one is considerably practiced in such off-trail travel.