ApproachHike to the bowl east of Glacier Notch and south of Mt. Gayley. This bowl can be reached from the North Fork of Big Pine Creek via Glacier Notch (class 3, ice axe and possibly crampons required if climbing from the west) or Contact Pass (class 2, ice axe required in early season), or from the South Fork via either Elinore Lake or the drainage that descends to Willow Lake (class 2, and the longest option of the three). An approach from Glacier Notch would be a curious choice (the peak is more easily and quickly climbed via its southwest ridge from that pass), so only the other two options are described in detail:
Contact Pass: Hike up the North Fork trail to shortly before Second Lake, where a good use trail leads down to a bridge over the lake's outlet. Hiking directly towards the pass from here involves tedious sidehilling over large scree and small talus; it's better to hike along the southeast shore of the lake before picking up a sandy use trail that switchbacks up to the bench above Second Lake. The use trail turns south from here and leads up through loose scree and talus to the pass. From the pass, contour southwest below Temple Crag, past several small tarns and snowfields to the base of Mt. Gayley's South Face.
South Fork Big Pine Creek: Hike up the South Fork trail to the signed junction for Willow Lake. Follow a use trail down past the lake and along the south bank of the creek that drains the bowl between Mt. Gayley and Temple Crag. The use trail crosses the creek just before the marshy area shown on the 7.5', and follows the north bank of the creek amongst boulders. The trail grows fainter past the turnoff for Elinore Lake, but cross-country travel is easier in the upper reaches of the drainage with slabbier terrain. The route meets up with the Contact Pass approach in the bowl south of Temple Crag.
Route DescriptionFrom the bowl south of Mt. Gayley, scramble up talus and slabs to the base of the peak's south face. A very prominent U-shaped notch on the peak's east ridge is a useful landmark; the route ascends the weaknesses in the face to the left of this notch, leading up to a much smaller notch along the skyline, just left of a small but distinct rock outcropping. (This is basically the first obvious weakness seen in the south face of the peak while hiking over from Contour Pass).
The lower portion of the face is mostly third class over broken rock (many options), with one or two short class 4 chimneys encountered along the way. The left side of the face consists of cliffs, so following the weaknesses generally leads up and right. The crux comes high up on the face, where a short, broken headwall that leads to a small notch along the southeast ridge is encountered. The easiest option here ascends the left side of the headwall via a steep, right-facing corner with good handholds, but not much for the feet--rock shoes are very helpful here to climb this securely. This is probably in the 5.5-5.6 range, but the section is short, no more than 10-15 feet or so, and only mildly exposed. Above this, easier ground (class 3) leads up to the ridge. Once atop the southeast ridge, a short scramble over boulders leads to the summit.
Descent: Descend via the southwest ridge (easy class 3). If returning via the east side of Glacier Notch, it's best to make a gradually descending traverse to the east (class 2); a direct descent to the southeast leads to cliffs. (These can be downclimbed if necessary--class 4--with careful route-finding, although lazy climbers seem to make a habit of rappeling here judging by the abundant slings left behind).
A note on the rating: Secor rates the south face of Mt. Gayley class 3, commenting only that Pete Starr descended it in 1931, and that the route "involves climbing over some huge boulders and small cliffs from the South Fork drainage." While descending the southwest ridge, there appeared to be one or two chutes west of the summit that lead down to the South Fork drainage. It seems likely that one of these is the third class south face route to which he refers.
Essential GearThe fifth class section is short (no more than twenty feet) and relatively unexposed, so it's not worth hauling a rope and gear up just for this. (If uncomfortable with climbing this unroped, the nearby southwest ridge would be a better choice). Rock shoes are helpful, if not essential, to climb this short bit securely.
Ice axe/crampons may be useful for the approach via Contact Pass in early season.