I commute 8 hilly miles each way on my commute and sometimes get out for a few miles at lunch. I don't train long distances at all. I just went on a bike weekend (BRAG Spring Tune Up if you are from Georgia) and rode 60 miles on Saturday and 40 miles on Sunday. This was the best I have ever felt on this distance. Consistent shorter distances are my new solution for training. I have a triathlon coming up and I think all my training will be commuter training.