You'll be hard-pressed to find a trail in Colorado with views this good and crowds this low. Even on a Saturday in August, you're not likely to see more than 10 people the entire time. That is unbelievable for the main trail in a National Park, let alone one with views of this caliber. Along the trail, prepare for an expansive look at 2 billion years of history cataloged in the rock record and revealed by the raging waters of the Gunnison River.
This run begins from the ranger station on the North Rim of the Black Canyon and continues down the trail through sage, oak, juniper, and pinyon before arriving at a series of mind-blowing overlooks. The most significant overlook is the aptly named Exclamation Point, which affords some of the most spectacular views of Black Canyon in the entirety of the park. Don't forget your phone, because you'll want to take pictures.
From there, you'll begin steadily climbing Green Mountain. From Exclamation Point, the vertical gain is around 900' over the course of about 2 miles. Switchbacks help to reduce the grade a bit with a few intermittent stair sections. Upon reaching the top, Green Mountain provides a 360-degree view of the area, including an additional perspective of the canyon.
Summer is one of the best times to experience this run, as rains make the trail nice, soft, and relatively free of rocks. Be sure to bring water along with you, but know that there's plenty of shade along the way.