To the OP, I'm over on the other side of town -- in flatter Lorain County. My work commute is 12.5 miles each way, and I try to ride my trusty old steel steeds at least twice/week in our too-short Summer riding season. I've always maintained a 80-95 cadence since attending Ohio State and riding with the OSU Cycling Club. I was also introduced to riding old-school rollers back then as a tool to not only for maintaining conditioning during the Winters, but also to develop a smooth pedaling technique. Smoothness begets efficiency! With that added efficiency comes speed for the same energy expended. With my 'natural cadence' and my commuting terrain, I'm usually in a 75-85 inch-gear, that gives be riding speeds of right around 20mph. I don't think that's too bad for an over-60 that is 40 pounds overweight! Spinning at my 80-90 is easier on my old knees as well.