Back to the Horsetooth Mountain Ride map.
The middle part of the Spring Creek Trail is a classic, mellow singletrack winding along through open meadows. As you head uphill, the Wathen Trail intersects it from the left then the Harrington intersects it from the right. I don't suggest trying to climb up and out of Spring Creek on either of those trails; they both make better descents.
About a mile uphill from the intersection of the Spring Creek and Harrington Trails, the Spring Creek trail splits. Taking the right-hand half of the Y, you'll climb up a jeep road-looking section of trail that takes you several hundred yards to an intersection with the radio towers service road. Taking the left-hand turn would send you up the upper Spring Creek Trail. If you are trying to climb on your bike, this would be a mistake. That section of the Spring Creek Trail is a double- black diamond technical descent, and just plain impossible ascent. If you climb this with your bike, you will wind up carrying it.