This trail might be one of the best hidden gems in the northern Front Range. Lower Dadd Gulch Trail has a healthy grade, a bunch of stream crossings, and is far enough away from any major cities that the traffic on the trail is minimal. The ascent isn't very challenging and the grade is moderate. Once to the top of the trail you have the option of doing a lariat on un-shaded fire roads or heading back down the way you came.
All in all, it's a very fun trail and worth the drive. Link it up with Hewlett Gulch on your return into Fort Collins for even more singletrack.