Conventional wisdom for the taper before a 100 mile race is to drop the mileage to 75% for the week ending 2 weeks before the event; then drop to 50%; then in the last week, just stay loose and run or walk nothing above what is required to stay limber. The purpose is to heal up any injuries or damage left over from the high mileage training phase.
I've started my taper week. Monday I did a walk/run of 4 miles and realized it was indeed time to taper. My right ankle was extremely sore at the top of the foot- dorsiflexion was extremely painful, to point of having to limp around afterwords. This was leftover, I believe, from all the climbing over the weekend; it may also be due to one fall I took where I caught my right toe and went down hard; I might have sprained it a bit; just not sure. (Fortunately I was carrying hand-air-bags, aka hand-strap running bottles. One bottle of red juice exploded on impact with the ground, a small price to pay for uninjured hands). I recall that after AC100 in 1991 this same joint/set of tendons on the right foot was swollen like a grapefruit. Anyways, after my Monday recovery workout it was painful to walk; I got home and iced it. Tuesday I decided to rest completely and iced it again; by Wednesday morning it felt fine and I ran 2x6mile double workout.
My plan is to run ~75 miles this week. On Saturday I will be taking my son deep sea fishing, an annual trip we take with some friends on a chartered boat out of Oxnard. This nice break with my son comes at a great time as it will force my taper! The following week I'll likely run a bit more than 50% but we will see how I am feeling.