i would think there would be enough people travelling Boston to washington , willing to pay a premiuim fare
Check out the Limoliner bus between Boston and NYC: 3-4 daily departures at $89 one way for a 4.5 hr avg ride with amenities:
Your choice of a variety of beverages: coffee, tea, soda, juice or water
Meal service: a light breakfast or lunch
Also a light snack service mid-trip
Free wireless Internet access at each seat
110 volt electrical outlet
Two DVD movies and live satellite television
5 different satellite radio stations at your seat
Current magazines
Fleece blankets and pillows
A large, clean restroom with hot & cold running water
Clear cell phone signal
http://limoliner.com/