Buckhorn Wash rock art
Some of the best rock art in southern Utah, right beside the road.
It may be quite a drive from I-70 but the road is good and this panel of mainly Barrier Canyon style pictographs is stunning. The rock art is right beside the road on a 130 feet wide panel. Highly recommended if you're in the area. This is a well-documented and popular site. You could combine it with a trip to the Head of Sinbad to make a full day of it.
To get to there drive west on I-70 from Green River for 29 miles and take Exit 131. The road parallels the interstate for about 2 miles before heading northwards on Buckhorn Draw Road for about 22 miles (from the highway) to a bridge over the San Rafael river. From here it's 4 miles further to the signed panel.
More rock art is to be found over the next 4 miles.