Thats everyone for your suggestions
Seems going by water will be the best and fastest, No need for a shuttle to BOS then a bus then the Blue or Red line. Providing its a calm day on the water.
I had googled the Water Taxi and couldnt believe it was $20 each way, then realized we want the Water Ferry and not Taxi. Maybe the hotel should KO the pic of the Hotel with the Water Taxi in the foreground.
But since the dock is walkable that gets the win.