The Disappointment Cleaver route on Rainier is the most climbed route on the mountain, and is among the least technical. With Rainier Mountaineering guiding the majority is their clients up this route, the Cleaver sees a lot the approximately 10,000 annual summit attempts. This is a long strenuous climb (9,000 vertical feet) and demands solid aerobic conditioning. $30 climb fee per person. Call the NPS or see their web site for the latest permit regulations. The Ingraham Glacier route is an alternative often used in early season when avy danger is high on the Cleaver route. Try it on a weekday for more solitude.