I'd put off going to Castlewood Canyon because it's a long way for me, and I feared it would be too short, and too crowded for a run. However, since I took it easy last week and I have a state parks pass, it was the perfect time to head down there.
There are apparently 12 miles of trails, and there is a nice top-to-bottom 8-mile figure eight to run, which takes you both along the creek and on the high bluffs. It was cloudy at the start.
The Lucas Homestead ruins:
At the north end, I headed up onto the Rimrock Trail, somewhat like a smaller, greener version of Pollock Bench in Fruita canyon country.
Distance was 8.40 miles, 2:02:41, avg. pace 14:36, moving pace 12:53, max pace 7:00, elevation gain/loss 1,135 feet.