“A flat, mostly-gravel loop with cool wildlife.
— Pete Sunden
There is some construction but it is navigable on bicycle.
Family Friendly: Mostly off-road trail riding with restrooms, animals, and no difficult climbs.
There are several free parking options just before crossing into the Rocky Mountain Arsenal National Wildlife Refuge (no bicycling inside of the Refuge allowed). If going counter-clockwise grab a number of gravel trails heading to the west that ultimately turn you north onto a paved section abeam Quebec.
Keep right at the trail's fork near the Quebec/2 intersection, back on gravel for the majority of the ride. Expect some gentle slopes. The northern and eastern sides offer some wildlife-viewing potential. Once you're heading south, you'll eventually wind up on the unmaintained Buckley Road.
After returning right at the parking lot near Pena Blvd on 56th Ave, you'll want to work your way to the opposite side of the road. You'll have some time on a wide, dirt shoulder that will eventually disappear. On the "wrong direction of travel" if riding west, there's a broad paved sidewalk.
Take 56th Ave to Central Park Blvd and turn right. There's a bike lane here that will eventually vanish in the construction areas, but you'll be able to piece your way back to your vehicle, some on roadway, some on gravel.
Overall, a nice and easy loop that has good training value for gravel. Keep an eye out for birds of prey and large land mammals.