To get to the true summit point, which is about 50 feet west of the end-of-trail lesser east point, requires the ability to climb a wickedly exposed 10-foot section of class 3+ knife-edge rock. In my opinion it's actually class 4 due to the level of exposure--both to the left and the right. Plus, it's harder to get back down it than to climb up it. You definitely want to beware of this.
As of 5/13/07 There are several trees blocking the road about 1/4 mile from the mountain loop highway. This adds about 3/4 mile on to the approach. I expect they'll have the road cleared by June or July.
The Forest Service announced today, 9/29/08, that the Perry Creek Road is to be permanently closed. Their plan is to expand parking at the Mt. Dickerman trailhead and build a connector trail from there to the Perry Creek Trail. I just confirmed with the Forest Service that the change will add 3 miles round trip to the trail. That means the long 11.5 mile day hike to the summit of Mount Forgotten will soon be a 14.5 mile overnight.