Climber’s trailhead is located half mile down from the Cascade Pass trailhead. There is a trailhead signpost next to the pullout and it’s fairly noticeable.
Majority of the elevation occurs at the beginning, then tapers off at the bottom of the Quien Sabe Glacier. More aggressive elevation gain picks up from top of the glacier just below the col between Boston and Sahale peaks.
Class 3 scramble from the col to summit, may or may not need a hand line depending on your comfort level with the exposure.