Gallup North Hogback Trail
The trailhead is just to the northwest of the Red Rock Motorsports area. The gate is always open so just drive on through, watching out for any friendly throttle-twisters and hydrocarbon folks.
The trail climbs very steeply on switchbacks and stone steps at first. Just pushing and carrying your bike is a good workout. Once up on the ridge, a more moderate trail heads south. There are a few hike-a-bike sections, but most of it is rideable and the views and a general airy feeling are great.
Where the trail goes over the ridge top and angles down the east side there's some pretty good cliff exposure. Use care here. Ahead, a spur trail heads south to intersect the highway. The main trail then turns north, running up a narrow valley and passing some of the famous Gallup cairns. After awhile, it gets sandy and then turns into doubletrack. Some of this is steep and technical, so watch out for loose stuff.
At the end, the trail bends around to the west and returns to the trailhead following a gas line.