Since there were two requests, I'll post my input.
The Bostonian is right next to Faneuil Hall Marketplace. There
is a "food court" or more like a "hall", selection is a little
better than most mall courts but that isn't saying much :-)
I don't get out to Boston too much anymore, but Country Life is still
there, I think, & pretty good & inexpensive (vegan buffet). It's walking
distance from Faneuil Hall (very close to the aquarium) but you will see
more construction than you want. If you have a big expense budget I
recommend the Harbor hotel dining room, whose chef can do VLF (veg on
Legal's in Copley Plaza is not that bad, they have a veggie gazpacho for
summertime and great steamed rice & veggies, and great sorbet for dessert :-)
Recently we've been to:
Blue Room: Red line to Kendall Sq. (+ a few blocks walk), at one Kendall Sq.
They had interesting veggie choices and I can usually eat LF if not VLF.
Salamander's: Really "interesting" presentation, some things were great
but we overall didn't think it was worth it.
Hammersley's Bistro in the South End (I think you can walk from Copley
Plaza...).. we take people out regularly there, & for birthdays, etc.
There are always several veggie options on the menu. They have outdoor
seating now, which is first come first served I think.
Jae's.. somewhere in the South End (we go to the branch in the burbs)...
korean/Japanese/french/whatever, sounds weird but most of their food is
very good. Lots of veggie sushi options, and cooked veggie dishes too.
Chinatown (can walk or take T to State or Boylston) has a veg place but
it was very greasy, I didn't like it at all.
Hope this helps. enjoy Boston & try to catch the Leonardo exhibit at
the museum of science! (btw there is edible food there, the sandwich shop
can make a veggie sandwich upon request w/no cheese :-)