When Susan Bacher’s officially designated month of grocery shopping by bicycle ended, she hoped she would maintain some of the standards she had set for herself in improving her fitness and reducing her carbon footprint, even as the prospect of colder weather would make biking more daunting.

The Carlisle resident did not anticipate the more dramatic change her life would take later in the fall when an opportunity arose that she couldn’t turn down: a part-time teaching position at an independent school in Wellesley.