Well, it's Friday night now, so it may be too late.
But, I measured the mileage from Brigham & Woman’s hospital to my driveway in East Providence (Riverside, the farthest part from Boston) with the car. It's only 55 miles.
To the west side of Providence may be about the same or a mile or two longer. More west but not as far south.
I went down Jamaica way to 138 to 123 to 152 into East Providence. You would have to go across Providence to get to the west side. It's a nice route from Boston if you don't mind riding in, or next to traffic. I'm riding up and back on Saturday. I have already ridden over half of the route before. I like it. Most of the way is nice. Part of it is narrow and has some potholes.
Skip route 1 if you can. Route 1A is better, but not as nice as this route. This is a lot less city and more rural.