One day a week? Piece of cake. Riding that distance every day would be tough. My round-trip commute is about 22 miles, and I ride 3-5 days/week depending on the weather and my work schedule. I was in good shape and riding a lot recreationally when I started bike commuting, but riding to work day after day was tougher than I expected. Here are some tips based on my experience:
- Start out riding 1-2 days/week to see how it works out and build up to more days.
- Research your route carefully so you are taking the safest roads, not necessarily the shortest or fastest.
- Make provisions to carry your gear in a large seat bag or rack bag rather than on your body (eg backpack).
- Good some good front and rear lighting.
- Don't feel guilty about driving when the weather is lousy.
- Get some good cycling clothes -- in bright colors -- that you can layer.
- Use SPDs or other style of mtn bike pedals rather than road pedals, which are harder to clip and out of in traffic.
- Just do it. You'll figure out what works for you with experience.