Have been up this peak many times -- the Ninemile Creek area (of Divide Range, as some call it) has numerous fun scrambles and relatively few people. While a trail works up most of the way towards McCormick, the last half mile of scrambling through large slabs of boulder is a treat, if you so choose this route. One can also work across the small canyon to the east and climb up Blackrock on the same trip, if they so desire.
This particular trip to McCormick was my most memorable -- fresh fall snow, mesmerizing cloud transformations, and a summit shrouded in a veil of ethereal clouds.