Rocky Mountain National Park has lots of high mountain climbing options. This one was recommended by a stranger last year. Blitzen Ridge is an amazing ridge scramble with exposure, good rock, and thousands of uphill steps. According to onliners the crux of the ridge is the Four Aces, four piles of stone that you must scramble over before reaching the ridge proper. Once defeating the Four Aces there's still a lot of rock to climb. Actually, some of the best scrambling is to be had after completing the challenging Fourth Ace. The scramble ends at the summit of Mount Ypsilon, a 13,445ft peak that can also be reached from the Chapin Pass Trailhead.
Blitzen Ridge is reached from the Lawn Lake trailhead. From there you go up to the trail to Ypsilon Lake then take the less used trail up to Spectacle Lake. From there travel below the first Spectacle Lake and up onto the ridge