This is a spectacular dayhiking area, with a number of options available to create a loop. Hiking up the west face, it's 2 miles to the summit, whereas from the east it's 3. My personal recommendation is to start on the old Bunsen Peak road, traveling three level miles to the intersection with the summit trail and the Osprey Falls trail. The walk is through a beautiful meadow with ever-changing scenery, but the sun will likely be in your eyes if you start out in the morning. Osprey Falls is a very worthy side-trip, and will add from 2.8 to 4 miles to your hike (I've seen conflicting reports). The trail swings back to the south along a dramatic bluffline, providing great views into Sheepeater Canyon before beginning the 800-foot descent to the falls. The trail is slippery, and steep in a few spots, but the awesome sight of the Gardner River spilling 150 feet down a gorgeous hidden canyon makes it quite worthwhile. Back on top, there are several nice resting areas along the bluff where you can catch your breath before beginning the long ascent of Bunsen Peak. It's a little difficult to find the trail, which begins directly across from the Osprey Falls trail. Look for cairns and markers, and when all else fails, head uphill until you reach the next identifiable path. Once you've reached the nice 18-inch wide trail, you shouldn't have any more problems. The burned skeletons of trees keep you from having a perfect view, but the scenery is still quite stunning. Once on the top you may notice a metal box with a rock on the lid; if you choose to read or add a note, please use caution. The heavy gusts of wind up here could easily toss the entire contents down into the valley. Going down the west side, each switchback opens up a new and spectacular view, arguably the best scenery on the hike. Going to Osprey Falls, the total elevation change is around 2200' or so in 11 or 12 miles. Skipping the waterfall but looping around on Bunsen Peak Rd, it's closer to 8 miles and 1350'.