Let me just add to Mike's post:
We finished with about 50.5 miles and averaged 13.2 mph. The middle of the ride was roughly 25 miles of mostly flat road (the Interurban), but the rest of the mileage was in pretty hilly residential and business areas. Those miles got to be a bit taxing. In the end, according to my GPS, we burned 2,499 calories, and that's a real plus.
I don't know about this 100-mile stuff Mike is talking about. -- Rob