This is likely the easiest route up (and down) Ingalls Peak. I could not make much sense of Beckey's description of the class 4 Southwest Face, but with a bit of looking around was able to piece together an interesting third class route up the peak. The scrambling is occasionally exposed but not particularly difficult, but I have a soft spot for improbably easy routes up otherwise hard peaks. The route may also be of interest as a descent option for climbers soloing the South Ridge who don't want to bother carrying a rope up there.
Gain the Ingalls-South Ingalls Col as for the South Ridge. (This is best done by following the trail almost all the way to beautiful Ingalls Lake, where you can hike up easy slabs much of the way to the col. You can also reach the col from earlier on the trail, but that involves negotiating more talus).
From the col, make a gradually descending traverse a short way below the west side of the ridge, following signs of travel through the scree. It is not necessary to drop very far.
The route begins at a light grey slab that abuts a cliff on its right side. The start can also be identified by the face being more broken here than to its left, where it becomes very slabby; to the right are cliffs below the South Ridge.
Climb the easy slab and/or blocky class 3 to its left (loose rock) up to a large boulder on a ledge, which had a couple of old, faded slings as of August 2018. This is the hardest bit of the scramble. From here, the route is easy to describe: Simply follow the obvious ledge/ramp system (occasional cairns and rappel stations) around and up to a small notch on the peak's northwest ridge, essentially hugging cliffs on its right the whole way. Almost the whole way is no more than class 2, with only a couple of short class 3 moves, and while there are some small ups and downs, you never have to drop more than 10-20 feet during the traverse.
From the notch (which I believe is the same one Beckey references as part of his recommended descent from the South Ridge), the northwest ridge is followed over scree/talus to the easy summit block.
The route is also simple to follow on the descent: Follow the northwest ridge down to the first small notch, and then follow the ramp down, hugging cliffs on the left. At one point the ramp appears to end abruptly at a steep cliff; scramble left up and over a small, easy slab to continue the traverse over to the aforementioned boulder and initial grey slab.
None required. The difficulty is similar to that of the East Ridge on Lundin Peak, perhaps just a little harder.