Ah...yes. I can't think of another boulder like this in SD. Start as far back as you can in the tunnel, underclinging the lip, and invert. Traverse the roof like this for about 20 feet, which feels secure until the shin-pump kicks in, then bust out the final pumpy lieback moves into good hand jams. Mantle into the big v-slot and take a few minutes to recover. You've got the bends...
North of the obvious Rain Gutter Boulder, and almost directly east of the Summit Towers, in a big cluster of boulders perched on a small hill.