Ray - I was talking with one of the scout leaders about doing Langley next year. It's high on my list.
Our longest day was about 13 miles, the shortest was about 2 miles (the last day, from Lone Pine Lake to Whitney Portal - we weren't going all the way out on Friday because the day had been long enough already, with plenty of vertical to summit and descend on the east side, about 2900' up and 4700' down).
These scouts were fairly young, ranging from 12 to 15. The youngest was a real trooper, never complaining and always smiling, despite the fact that his pack was almost as big as him.
Since our entry point at Onion Valley is in the Inyo National Forest (INF controls the Whitney zone on the east side) we also had to get exit permits for Trail Crest on Whitney. If you start outside the INF, you don't need to get an exit permit. When I did the route from the west side of the Sierras across to Whitney in 2006 (starting in the Sierra NF by Kings Canyon NP) I did not need to get an exit permit, my entry permit from Kings Canyon was all I needed.
I am heading back out on Saturday for an eight day loop in Kings Canyon that will be more challenging, and will get me to some spectacular places that I have always wanted to visit. About half the route if off-trail. I have room on my permit, anyone else want to come along?