Left chute: I did this one in 1997 with David Sandwell. It's described in the Secor Book, but until the 3rd edition was incorrectly stated to be the right chute. We had the 2nd edition and were initially quite confused until we figured out that the description had to be for the left, not the right chute. About half-way up the left chute, one traverses right and descends to the middle chute, then follows it to the summit ridge.

Right chute: I did this in August 2014 with Jeff Gee and Rick Aster. It's about equal in difficulty to the left chute. The trickiest part is that at the very top of the talus fan one needs to climb left onto the ridge to the left of the chute. It's easier than it looks at first. The ascent up the ridge was well marked with cairns in 2014 and leads to a chute that can be followed to the summit ridge.

Mt. Darwin has a flat top, but the highest point is on a detached block at the south end. In 1997, we did not attempt to climb this. In 2014 we brought a rope (30 meters is plenty) and used it to complete the climb. Facing the block from the main Darwin massif, one can descend to the right, cross through the notch and descend down the talus to the left. After dropping about 50 feet, one can traverse around the block and ascend a gully/crack to reach a point directly behind the block. Gaining the top of the block requires about 5 to 10 feet of Class 4 climbing. We used a rope and a couple of small cams for this part. I probably would have been OK going up without the rope, but the downclimb would definitely have been scary. From the top one can rappel to the notch with a 30 meter rope. There were several slings and a rappel ring in August 2014.