Why in one day ?
IMHO- it is overly simplistic given the traffic dynamics.
Your start/end locations would make a huge difference in the travel time. For example in NYC would you be starting in lower Manhattan say near Battery Park or from Staten Is or the Bronx ? and going to where in Boston ? Eg, the Haymarket area or Back Bay ? Suggest a two day ride each way with time to take in the sights and perhaps a day layover in Boston.