I started at Sugar House Park and followed the trail all the way up to the Grandeur’s Peak Trailhead, then looped back.
The elevation is brutal: first off, you’re at or above 4000 feet the whole time so the air is thin. More importantly though, over a 3 mile strech (starting just less than a mile into the run) you climb 1100 feet.
I ran this on a cold April day and it was tough but satisfying. Much of the run follows a highway but is separated enough to feel comfortable, and the incline is so significant that you really feel like you’re running up into the mountains.