Be sure to get the cell phone numbers of the SAG wagons. I had a busted tire on a supported ride and was in the middle of nowhere when it happened. Still took them 30 minutes to arrive but better than walking the twelve miles down the mountain to the next rest stop.
Charity centuries around here have the rest stops manned by volunteers and on a couple of the rides they provided all the food and water/gatorade, too. So be sure and thank them for their efforts. I hit a rest stop on the Leaves of Lincoln century ride that was giving free leg massages. At mile 82, that really, really hit the spot.