The outer- Boston suburbs of Lexington and Concord might sound familiar from past history lessons—and they might just be New England’s most underrated day trip . Just 30 minutes outside the city you can leave Boston behind, retrace Paul Revere’s midnight ride through still-rural areas, visit the real-life setting of Little Women (as well as its author’s gravesite) , and walk the very fields where the American Revolution began. Nearby there’s still more to discover; browse independent bookshops, swim in Henry David Thoreau’s magical Walden Pond , have a farm-to-table meal, and be back in Boston in time for a nightcap—unless, that is, you’d prefer to stay a while at a local inn that’s also a Relais and Chateaux property. If you’re looking to enrich your visit beyond Boston, this is a magnificent use of a day (or two).…