http://www.fcgov.com/naturalareas/pdf/foothills-trail-brochure.pdf and reviewing the route with Google Earth or Google Maps. Here is a screen shot of my GPS route loaded in Google Earth.
Trail Stats
Round Trip Distance = 14.1 mi
Total Elevation Gain = 1836 ft
Ride Time = 2.5 hr
Trail Type = Several technical sections (rocky)
Trail Walkthrough
Start from the Maxwell natural area parking lot (coordinates: 40.555931,-105.143823) and head south on the trail. When the trail splits at Dixon reservoir keep right. The trail will take you along the side of the ridge, almost to Harmony road and loop back around the other side of the lake. Part of this trail was closed due to muddy conditions when I went, so I had to cross over to the other side of the loop.
View from the southern end of the trail facing Dixon Reservoir
Dixon Reservoir and Dixon Canyon Dam
After going around Dixon Reservoir ride north past the parking lot into the Maxwell Natural Area. Pass by the stadium, stay to the left and head up the ridge towards Horsetooth Reservoir.
Rocky section in the Maxwell Natural Area
View from the north side of the parking lot facing north.
View from the north end of Reservoir Ridge (facing south)
Instead of going back on shoreline trail, head south on Centennial drive for a short distance until you reach a trail that follows the road on the right hand side. This will eventually cross the road and enter Maxwell Natural Area. From here head back to the parking lot.