FYI - There's a fair number of stairs as you mount the Gilmore Bridge from Water St but there is also a public elevator if you need it. The sidewalk on the bridge is wide and protected by a concrete barrier.
To add to this, a short hop away from Notch in Brighton Mighty Squirrel has a restaurant/tap room at Arsenal Yards in Watertown. MS is sort of so-so, but I have heard the food there is really good.
Should've done that before I replied lol Is that bridge better for pedestrians than it is for driving on?