I have done 5 centuries this year, 2 organized and 3 solo. Two of the solo centuries weren't supposed to be solo, I was riding with one other person. In both cases he bonked at about mile 70. I still can't figure out why, I probably lead about 50 of the first 70 miles. Then the last thirty in each case was ride 5 miles, turn around and see he was not there, then wait at the next turn, then repeat the process again.
I do not really want to do centuries, it was just a goal I set for myself to do two. One was to complete an actual ride (Mt Mitchell), the other was to do one in under 6 hours w/stops. Managed both of those goals. So as of right now I am goalless for next year, as far as centuries are concerned.
I have no desire to ride more than 120 miles in any one day.