Mike H, the Crabtree Lakes route is fun. I went through there two years ago, coming from Horseshoe Meadow. Having a gps unit might help find the start of the trail. Last trace of the trail around Crabtree Meadow is here:
https://caltopo.com/map.html#ll=36.5571,-118.3504&z=20&b=sat&o=mbt&n=0 In the dry sandy area. All the meadow vegetation has wiped out any trace. Once you find that starting trail it is pretty easy to follow. Middle lake has a great sandy beach. Perfect swimming (or camping) spot.
Due to the bare granite, it really doesn't exist between the middle and upper lake. I descended the west side of Crabtree Pass. I don't recall anything bad. It will be your steepest climb, maybe third class.
I climbed the slope west of the middle Soldier Lk (36.5055, -118.2707), and then walked the contour until I hit Rock Creek. But that was because I climbed Langley, and then descended to the upper, then middle lake.
It's a pretty area. You should do it!!
P.S. If you haul your gear up to Trail Crest, you could descend directly to the upper lake from Discovery Pinnacle. The sand would make a fun descent, but you would miss the Crabtree Lakes experience.
