Upon approaching Icehouse Saddle there is a sign to your left that marks the trail to the Three T's. The three T's are Timber, Telegraph, and Thunder Mountains. The trail will take you near to the peaks of these three mountains and will eventually drop you off near the notch where the trail continues on to Mount Baldy or down the ski slope. This trail is more strenuous and takes a fair amount of time. It should also be kept in mind that the trail ends at the notch. If you're hiking in a group it may be a good idea to have cars parked at both the icehouse and the ski area park lots.
Henninger Flats is a small hanging basin 2600 ft above sea level in the San Gabriel Mountains in the Angeles National Forest. It was part of the Mount Wilson Toll Road. The trailhead to reach the flats is at the top end of Eaton Canyon in Altadena.