This was formerly a nice route up the peak and one of the the most scenic routes up the mountain, but the latest information says that the trail has mostly faded away and is now a bushwhack.
I did this climb back on June 10 1989.
Drive up Provo Canyon to Vivian Park and turn right at the South Fork Provo Canyon Road. Drive to the South Fork Park picnic area. Park here. The trailhead is at 5440 feet elevation.
This is a very scenic route up Cacade Mountain, and the scenery is similar to that of Mt. Timpanogos to the north, but without the larger meadows.
There is a ranch (Giles Ranch) at the mouth of Bunnells Fork, but the owners allow hikers to walk through the property. Don't attempt to drive a vehicle in.
Note: Perhaps this information is outdated. I haven't climbed this route in several years.
Walk through the ranch and up Bunnells Fork. The trail is slowly disappearing due to light use and will start to fade some time in the future. (Update: It sounds like this trail has now faded mostly away and that there is more bushwhacking then there was in the past).
Walk the trail up the beautiful Bunnells Fork Basin. The trail is easy to follow at first, but slowly fades. It basically disappears near some waterfalls just above 8,000 feet. Continue up the basin and routefind over the cliff band with some waterfalls. Once above the waterfalls, the summit is visible, so just head up the steep basin and to the minor saddle between the two summits. The last part of the route before the summit ridge is over extremely steep scree and care must be taken.
The highest summit is the one to the south of the saddle. The total one way distance to the summit is 4.6 miles with about 5500 feet elevation gain, and since much of the route is trail-less, this is a long all day climb.
Note: Don't attempt this route in winter or early Spring as the route is too avalanche prone
A good pair of boots is needed in summer. An ice axe is recommended before late June.