We drove up the Icicle Creek road to the trailhead, all tread in good shape. The Jack Creek trail is also in fine condition for the 5+ miles. Here we took the path towards... oops, forgot the name of the creek... which goes for a short distance until it crosses Jack Creek. There is no bridge, but it's a pretty easy wade at this time of year. Actually we found a logjam that can be crossed slightly downstream.
Just across the creek, if you go upstream a short distance, is an old abandoned trail (shown in the 1973 Greentrails map). This was probably a sheepherder trail. Tread disappears several times but try to get on the ridge towards Harding Mountain. Here you'll find good, obvious tread. At one spot we found a sign saying ""Stock Driveway"" with a U.S. sign. It's pretty rusty and hard to read. Our objective was Harding Mountain, but the trail traverses to a meadowy area at about 5200 or 5400'. We gave it up and climbed to the summit. Nice to find this route though!
Jack Creek is well-maintained with only a few minor logs down. Harding Mt has plenty of logs down.