Each segment of your journey: Boston to Maine; Maine to Quebec City; Quebec City to Montreal; and Montreal to Dartmouth, can be driven in 5 hours or less using the fastest roads, usually Interstates in the U.S. and Autoroutes in Quebec. When you say the "best route:" if you have time on any given segment, consider venturing off onto smaller, more scenic roads, and let serendipity happen to you. New England can be VERY scenic.

By the way Boston to the beginning border of Maine is short; it can be done in a hour-an-a-half to two hours, if not rush hour or the start or end of a weekend (Fri. evening, Sun. night). On the other hand, you can spend five hours or more driving the fastest route to a point farther up the coast of Maine (Down East, as the Mainers say).

--Charlie Baum