The Whitney Mountaineers Route is a fun Class-3 climb on the most direct route up to the top from Whitney Portal.
Dawn on Whitney from Lower Boy Scout Lake
Start on the Mt. Whitney trail till you cross Carillion creek and reach the North Fork of Lone Pine creek. The North Fork trail is on the right just before the creek crossing. (If you see the 'John Muir wilderness' sign, you've gone too far - come back down the trail and cross the creek and you'll see the trail to your (now) left).
The trail is fairly well trodden and should be easy to follow. It is also easy to lose. You'll start with the creek to your left - and after a quick steep climb, cross over to the other side. A common place to lose the trail is a few minutes after this creek crossing. If you find yourself starting at a blank wall, you've missed the trail ~10m behind you (The trail heads down towards the creek - not away). There are a lot of use trails around here - don't take any of those or you might end up on unnecessary scrambles that go nowhere.
The trail crosses the creek again and immediately after is the Ebersbacher Ledges. The path to follow on these ledges is fairly intuitive. You climb up the rocks that seem to block your path, turn around at the 'lone tree' and go downstream for ~25m before scrambling up some rocks to hit the trail again to go upstream. This takes you to Lower Boyscout Lake.
The trail cross the stream at the mouth of LBSL. Do not climb too high on the talus here - stay close to the vegetation and the trail reaches Upper Boy Scout Lake. Close to UBSL, the trail climbs up switchbacks to the left to enter a canyon. Stay high on the canyon (to the right) and the trail is fairly clear. At the end of this, you'll pass a waterfall (coming out of Iceberg lake) on your right and you have a wet class-3 scramble up to the lip where you'll reach Iceberg Lake.
From Iceberg Lake, the chute to take up to the notch is very obvious. Stay to the left on this chute (on/close to the rocks) and avoid the slippery sand/rock/talus. At the top of the notch, descend ~10m and the class-3 chute to the summit plateau is on your left. (Alternately, you can go past 2 chutes to reach the summit on a class-2 route). This chute has some snow at the center of the bowl. I traversed to the right of the bowl (with the snow patch on my left) and easily reached the summit with some class-3 climbing. I did not find anything I would describe as a chimney that was referred to in many climbing betas.
Staring down Whitney from the canyon between UBSL and Iceberg lake
Iceberg Lake
The chute leading up to the notch - mostly class 2
Iceberg lake seen from the chute
Looking back from the notch
Looking north from the notch
Arctic Lake from the chute leading to the summit
The Great Western Divide from the Whitney summit
Iceberg lake from the summit
Pinnacle ridge that separates the Mountaineers route from the Mt. Whitney trail to the south
Hitchcock Lakes from the Whitney summit
View to the north-west: Arctic Lake and Mt. Morgenson
View to the west - Hitchcock lakes, Guitar Lake and the Great Western Divide
Lakes to the east of Mt. Whitney - from Iceberg lake to Consultation Lake
The class-3 climb upto the summit of Mt. Muir
View from the west side of Mt. Whitney/Muir
Consultation Lake on the way down the Mt. Whitney trail
Overview of the day:
~14.5 miles with 6700ft elevation gain/loss.
Total time, car-to-car = 13.5 hrs