My commute is about 14 miles, 28 round-trip, a bit hilly.

Seems to me this is due to the road design catering to automobile commuting. I would have chosen an 8 - 10 mile distance with roads designed a little more like railroad tracks: less hilly.

I guess adversity builds character, though! (I still only commute by bike about 3 days out of every week. I hope to build up to 5 days, for the same reasons people climb Mt. Everest: "...because it's there.")

I average 70 - 90 miles per week. (Not bad for a 42 year-old...that's over 6 hours of moderate-to-heavy exercise per week, over six times the minimum recommendation of 20 min. three times per week.)