Follow the directions on the main page for Old Man/Old Woman to reach the southern base of Old Man. From there, traverse west (that's left) following the base of the formation until you reach a gully between Old Man and some heap of rock immediately to its left. Go up the gully until you reach a side gully on the righ heading up to the Old Man - Old Woman notch (there's a mid-sized evergreen almost at the top of the notch, see photos). Route begins from the highest point in the notch.
Dilley's Delight climbs (mostly) the west face to the summit of Old Man. It is two pitches in length and the crux pitch (number two) is on solid (though heavily lichen covered) rock. This is the easiest route to the top of Old Man. Greg Orton provides a topo (photo with route superimposed on it) of this route in his guidebook.
5.6, ~80 feet. From the Old Woman-Old Man notch, traverse a two-foot wide, low angle ramp (class 4) for about 30 feet to the base of a somewhat dirty and vegetated crack/groove. Climb the crack up (5.6) until it crests inside a notch in between the Old Man and an adjacent flake. Belay on gear.
5.9, ~80 feet. From the notch, head straight up the 15-foot hand crack. I found this section to be awkward (more so than it looks). A bolt near the top of the crack (just where it becomes a groove) alleviates any apprehension. Scramble 15 feet over ledgy terrain and move slightly right (just above what the book calls a "cave" - in reality it's just a small horizontal shelf). Follow the easy-looking crack up (again, slightly harder than it looks I thought) for about 15-20 feet. The pitch has been restored to its FA status in 2008 thanks to the efforts of Greg Orton, Harold Hall and Corvallis
(after the crack had a short-lived encounter with a retrobolter in early 2000s). Once near the top of this crack (at last bolt), move right about 6 feet. The book calls this the crux of the route (only 5.9 move). It can be aided by using the last bolt. The move is probably not that hard, but there's not much friction on your shoes (lichen galore!). This brings you to an easy, low angle gully. Follow this dirty gully (5.4?) for another 15 feet to the summit of Old Man. Pitch 2 overview.
Do one double (we had 2 60m ropes; 2 50's would work as well) rope rap back to the notch where you started off of a set of three bolts (2 new, 1 ancient) with chains.
(pointed out by M_and_N_Denyer) If you have a single rope, rap off of the summit bolts back down to the notch (top of P1). From the notch rap back west (towards the direction you came up) using a sling on a horn.
The presence of bolts on the crux upper pitch reduced the need for a very large selection of gear. Still, this is not a sports route. Cams in the 0.5"-3.5" range (think we used a #4 Camalot in the easy gully near top of pitch 2). Helmets! Two ropes make the descent less of a pain.
Also, the summit makes for a great lunch spot. Lunch box optional.
More Route Photos
More Route Photos