The Sonic Youth Cliff is a NE facing cliff that is within perhaps 10 minutes walk of the Sandstone Quarry Parking lot. The cliff contains several lines, both trad and sport, primarily 5.11 and harder, though there are a few exceptions. The cliff is just far enough from the lot to escape the crowds of non-climbers, but as for how many climbers may be there, I have no guess. I was there on a bad-weather day. The rock is fairly typical of the Red Rocks lighter colored stone, with the exception of a few routes that are in solution-pocketed water streaks.
Park at the main lot for Sandstone quarry and head off north on the main trail until it becomes obvious to gain a trail to the west going up a hill to gain the ridge below Sonic Youth. From there, follow the ridge further N/NW to arrive at the base of the crag near your intended climb.
A good crag with a few great lines. The rock quality is still a little unreliable and don't be surprised if you break a foot here and there. You will also probably notice that some of the jugs you're holding onto are actually glued onto the wall. Still worth the trip even if you just get on Sonic Youth