Did the Giro de Bella 100K out of Sebastopol (CA) today. The local Rotary did a very nice job with this ride. The weather was perfect and the countryside beautiful: vineyards and horse farms mostly. I haven't done many 100K or Centuries on my single bike, but I was pleased to average 16 mph over rolling terrain (2700 feet of climbing). With a decent amount of riding over the next 3 months I should be able to do a sub-6 hour century a comparable feet/mile of climbing.