I have done this route several times and start/end at the Visitor's center Trailhead. It's to the left of the building, by the picnic tables, with a big sign and various distances listed for Moenkopi/Calico Hills, etc. When I figure out how to upload photos to this site I'll add a few. From the VC you curve around to the right, run the Calico's, and then Sandstone Quarry parking lot to Turtlehead Peak, which is 2.2mi or so from there.
From visitor's center: 2:03:49. 11.0mi with 3k of gain.
From sandstone quarry: 1:01:09. 4.2mi with 2k of gain.
Can't wait for my next visit to focus on just the climb. I'll try to post beforehand and see if anyone wants to join.
[note that Todd's Garmin link isn't public & we are unable to view the data]