I booked a night at the Hyatt near Logan Airport for later this month because the Hilton is twice the price on my date. As long as I keep my luggage on the light side, I might attempt walking there from Terminal A. That having been said, in the past whenever I've had similar aspirations at other airports (e.g. MCO, DFW), I've found that walking was impractical. I'll let you guys know how it goes.

ETA (from the hotel, having just completed the walk):
The walk from Terminal A to this place was honestly pretty nice, even with my moderately wieldy luggage. I'm not sure I would do it in bad weather, though. While the Hilton is far more convenient, I kind of like this place. I'm going to try the shuttle tonight, btw, when I greet my friend who is coming in later.