Through the eyes of Mary Paschall, an avid Mountaineer, the 1912 summer challenge was to explore "the least known parks and Glaciers" on the north side of Mount Rainier, "and finally to scale the great peak itself." Her account of the Outing appears in the 1912 Mountaineer Annual. Photographs taken during their journey bring this segment of history to life for us.

In 1915 The Mountaineers conducted their third summer outing in Mount Rainier National Park. With over a hundred individuals taking part, they became the first large group to hike completely around Mount Rainier. With a few modifications the National Park Service and the Rainier National Park Company later named their route the Wonderland Trail.