This is an unofficial route (steep and unsignposted) in a remote location that adds to its overall challenge. Only come here if your navigation is up to the task, and practice Leave No Trace to avoid damaging fragile terrain.

If you already happen to be passing Klapatche Ridge along the Wonderland Trail, the off trail portion of this hike is only 1.3 miles with 560' elevation gain. The challenge is getting there, which involves 7.8 miles (roundtrip) with 1000' elevation gain hiking or biking up the Westside Road, followed by 9.1 miles (roundtrip) and 2760' gain along the South Puyallup trail and a portion of the Wonderland.

Turn off the Wonderland at the top of Klapatche Ridge, immediately before it turns left to begin its traverse across to St. Andrews Lake. I found the path faint in places but clearly visible. It climbs very steeply up a meadow, after which you'll squeeze through a single row of trees and enter a magical ridgetop which in places is almost wide and flat enough to feel like a high plateau. Mark this spot in your memory so you can find the right place to descend! Continue up the ridge with a gentler gradient as views astound in all directions: Adams, Hood, St. Helens, Mount Wow, Pyramid Peak, over the Tahoma Glacier and headwaters of the South Puyallup River to Emerald Ridge, and of course Tahoma herself overlooking it all.

I turned around at the saddle just before the peak of Andrew Benchmark itself. To summit this requires traversing a scree slope to the right of the peak, then ascending from the far side. I didn't fancy that while carrying a full Wonderland backpack.