A few years ago, I trained for a long climb (not nearly as steep as this!) by riding on a rolling country road with no stops for 20 miles. I tried to keep my heart rate in a narrow range that I could maintain for the whole distance. It takes concentration to do this on flat roads, because it's easy to slack off the effort on the flats.
If I was going to try this climb, I'd install really low gears, so my cadence wouldn't be down in the 40s or 50s.
Even the top racers have special low gear setups just for this race.
from this blog:
Last year I watched Ned Overend ride away from me, with his ultra-low mountain bike gearing, something like a 24/32, as I slogged away in my 34/27. Don’t get me wrong, he would have climbed away from me even if we had the same gearing, but he sure looked more efficient spinning than I felt grinding. This year I decided to figure out a way to get a sub 1:1 low gear and at the same time be able to use my Quarq power meter. The solution I came up with was to use a SRAM XX 10-speed cassette and SRAM XX long cage rear derailleur, in conjunction with my RED double-tap shifters.
An old BF thread:
This is the only occasion I ever use a non-standard crankset. 33T/22T with a 12T-25T cassette.
Last year, I climbed two miles up Pilot Mountain--see this ridewithgps recording. The main climb averages 10%, with 15-18% switchbacks. I was climbing in my 34-29 low gear, standing on all the steeper parts. I weigh about 170.
On the main 1.9 mile climb, my average cadence was only 48 rpm, and average speed just 4.3 mph. This took about 25 minutes. I could have used lower gears if I had them. Mt Washington would be way too hard for me.
My lower back was sore after the ride. I should have done a lot of core exercises before I tried this.