I was based in BOS with my previous airline, over a decade ago. There usually are a decent # of crashpads available - often advertised on the crew room bulletin boards or other company forums. Also, ask around when you get there. You should be able to get there via the 'T' (public transit), although Revere or East Boston, where many are located, can be questionable neighborhoods.

Hotels are pricey if you use them as crashpads.