With your knees I would say the Ascent, 13 miles down an 11% grade is hard. I am only going to do the Marathon one time in 2018.
In response to:
I have qualified to do the Ascent. But won't run a marathon until October to qualify for the full marathon. Should I wait and do the full or just do the Ascent ? Need help to decide. With my bad knees I only have one shot.