Thanks for this very helpful description of the route. I did the hike yesterday, and it was a big help.
The suggestion to bring 6 liters of water seems a little extreme to me. Okay, I was doing it in late spring (May 21), not summer, but even so... I brought 5 liters, and ended up drinking only 2 liters of it (plus 1 liter before hitting the trail).
I'm not sure I agree with this part: "The use trail may fade in and out during the last 1/2 mile. Remember to to stay left of the very spine of the ridge." I found the use trail to be extremely clear and easy to follow, all the way to the summit. I also didn't see any places where it departed from the ridge-line at all. It's really a very straightforward slog up the ridge.
Re water: if you did the hike on a real warm day, I don't think 6 would be too much if you like to stay hydrated. 'Course, I wouldn't recommend this hike in the middle of summer.
Re the trail: it probably changes in distinctiveness over time. I've definitely been on it when you could lose it, but it is always easily picked up again. I've known people who tried to go just below the ridge on the right and had to reroute.