On the left side of the steep south face of the Happy Boulder.
Sit-start under the lip of the small cave, under or just left of the big hueco. Start with hands either on the thread hold or the outside of the hueco. Climb up the hueco to a big move to fair left-hand pocket and right-hand crimp (using any of a number of tricky sequences and lots of core tension!) Then, launch up the steep face and catch that perfect juggy hand-sized hueco just below the lip. Don't blow the topout. Your abs might be sore after working on this absolutely classic problem!
You're right.. my description maybe was misleading. I didn't mean to start way back in the cave, although that would be an entertaining extension that probably wouldn't change the grade of the problem. I start both hands on the left side of the hueco, feet below. I don't use the thread, but whatever sequence works for you. Good on ya for the send, I haven't finished it yet. On the top of my list for this season.