Congrats on working on doing a century - here in Oregon, there are several century rides along with a couple of double century rides during the season. This year, I have completed the Seattle to Portland -STP- (single day double century) and the Vine Ride (century, very hilly). The key for me in riding long distances is to be consistant with training (I ride between 100 - 200 mile per week). I personally work on pacing (cadence and gearing) so that I won't get tired to early. On this year's STP, my 200 mile average was 16.5 mph - no record breaker, but I completed the ride in one day - 14.5 hours (including my 4 stops)