With a very short approach, there are approximately 4 routes off the ground. Bloody Knees (5.9+) is the longest and requires a large rack with some large pieces for the wide crux, as well as two ropes to get off the route. This was one of my first leads, and I don't think it's too hard for an offwidth. The hardest is Oxygen Debt (5.11+) and by the looks of it, it will test your fist and offwidth skills to their limits. Bloody Elbows (5.9) is a good one for a small rack, and don't let the name intimidate you, it's not THAT bad. Another climb called Little Crack (5.9) is located right there as well, and it sounds moderate, but I haven't taken a look at the route yet.
This is a great spot for intermediate climbing. It is north facing, so it's in the shade and the approach is easy. I'm not sure what kind of sandstone it is, but it felt and looked hard and good to me. Possibly Wingate, but not superb Wingate.
There are also more 1 pitch free routes .5 miles up the road on the Anasazi Buttress. The River Road offers miles of opportunity for new routes from the 1 to 4 pitch range if you're ambitious.
Getting There
The River Road Dihedrals are located almost 3 miles up the River Road from the Hwy 191 turnoff near the Colorado River crossing. They are located just right of a canyon mouth, and a huge pillar with a spectacular and vicious splitter is located above the River Road Dihedral climbs. There is parking directly across the road from the climbs. Just up the road is the mouth of Negro Bill Canyon, and there are usually many cars and mountain bikers as the Porcupine Rim mountain bike trail exits here.
This area is Navajo Sandstone and it is good quality Navajo. The Wingate comes out of the water just up river from Negro Bill Canyon, look for it rising below Barney Rumble Tower...Pretty cool!