The part from Basin camp to the notch at 16,200 (the top of the Headwall) is the steepest part of the entire climb. Supposedly up to 55 degrees slope. There are fixed lines so bring an ascender if you have one. If not, you can still cliimb the Headwall no problem. During our first carry to 17,200 (High camp), there was a traffic jam on the fixed lines so I just climbed around the people for a good portion of the section - perfectly doable if you are confident with ice ax and crampons and use both your legs and hands...
Once at the notch, there is a ridge (called 16 Ridge) to your right leading to the small basin at 17,200 where the High Camp is located. This is probably most spectacular and technically most dificult part of the entire climb (still not technically demanding). There were fixed lines around Washburn Thumb (approx. in the middle of the ridge). The ridge is almost always at least couple feet wide so you get good footing, although the exposure on both sides is big - couple thousand feet.
At High camp (17,200), you have to use CMS cans to go to bathroom (I believe mandatory from 2004 season) - I praise NPS for enforcing that - when digging campsite we uncovered too many frozen feces from previous seasons. There is no ranger station here, NPS only stores rescue gear in a box at the top of the Rescue Gully here (we have witnessed this gear being used in getting a frostbitten climber down to Basin Camp for evacuation). Finding clean snow for melting water at this campsite was a challenge.
Summit day: From High camp ascend to Denali Pass at approx. 18,200. The route is pretty straightforward, you just traverse the slope. Be ready to self-arrest if you slip, the slope is a long one.
From Denali Pass continue below a ridge (usually marked with wands) to Football Field at approx. 19,500.
Once you cross the Football Field, you ascend the "summit headwall" which feels quite steep at this altitude to gain the summit ridge. Again, be ready to self arrest when ascending this "headwall". I have observed guided trips using running protection on this section.
In decent weather, views from the ridge are awesome. There is quite an exposure to the right of the ridge (direction when ascending). The ridge gains approx. 300 vertical feet and will take an average person 30 - 45 minutes to climb.
Then you are there. The summit is nothing spectacular, just a broad mountain top. No summit register either - :-))) There is a USGS marker - take a picture of it in case you need a proof you have made it to the top...
Roundtrip from High camp takes an average climber between 9 to 14 hours.
I highly recommend Colby Combs "Guide to West Butt" if you are thinking about this route.
Thanks for taking the time to write that!
Our party used Sheldon Air Service to fly in to Base Camp this past June, of 2014. For all my future Alaska mountaineering trips, there is no other air taxi service I would use. Besides the flight, Sheldon let our party sleep at their hanger, fed us a meal, lent us bicycles to ride into town, and let us lay all of our gear out in their front yard to dry out upon return. Friendly, oddly the cheapest, and a good business to support. I can't speak highly enough of them.