Not a normal hiking trail -- usually done only with good snow cover and safe avalanche conditions on skis or snowshoes. This approach starts from some other approach, up south from South Lake around (GPS latitude longitude approx N37.1528 W118.5771). At first SSW above W side of Treasure Lakes, and continue up drainage which leads to NE side of a narrow pass in the ridge (N37.1358 W118.5903). Finish up steep narrow loose gully (bring crampons?) to reach pass. Next contour NW along ridge, and curve up diagonal left (W) onto SE face (steepness sustained 30-35 degrees) and up that to summit of Mt Gilbert (N37.1368 W118.5984).