Some people head up the North side of the river from the Mount Whitney Trail. Some people head up the South side of the river, just after crossing the river. Starting on the south side, you follow the trail a ways. Then you climb up through a large boulder field. Next comes the large smooth slabs, or the trail winding though the bushes, just to the North of the slabs. About 1/2 but not 2/3 of the way to first lake, the canyon narrows, making it difficult to continue. When you look on the other side, up on the ledges, you will see a solitary tree. Cross the river and go a little west, and then begin your climb. The path goes to the tree, then goes east for maybe 50 to 75 feet. Then climb up 5 or ten feet and then turn west. It looks like a "Z" in the book Mentioned. From there it is mostly a straight shot up toward Lower Boy Scout Lake. Early in the year the snow covers up the bushes down by the river and it is possible to just keep going and work up the gradual ledges on the South side all the way to the Lake.