Well I decided to do this as my monthly Century Ride and I can report that it was very very tough! I did 100.4 mile with just under 9,000 feet of climbing!
I had a 30-34 bottom gear and used it a lot. I think there will be a lot of people walking on this, if they don't have low gears. Nice route with lots of temptation to cheat, so I hope it is well marshalled.
https://www.strava.com/activities/700448634
