I think BostonZest opened a seasonal openings this year, but no vacation thread yet. The bulk of these come in July and some in August but I just happened on one. Some restaurants which regularly take vacation which are worth calling first in July and hopefully folks will post exact dates include Galleria Umberto, Trattoria Toscana, Courthouse Seafood Restaurant, Royal Pastry, Izzys...
New Deal Seafood is on vacation from 5/30 and back on 6/6. (Courthouse is still open and probably Fernandes but I haven't made it down there.)
130 Jersey St, Boston, MA 02215