Wish I had seen this before, rather than after, the AHA, but going to post because it might help fill out some of your itineraries (including my own) on trips to Boston:
Meaghan Dwyer-Ryan, A Guide to Boston's Religiously Significant Sites, from the published supplement to the just-concluded AHA meeting in Boston. The author includes short descriptions and histories not only of the usual suspects (Old North Church, etc.), but also to major Catholic and Jewish congregational destinations. Put this one in your bookmarks.
Here's one I didn't know about, just for a little taste:
German and Polish immigrants established Congregation Ohabei Shalom, Boston’s first Jewish congregation, in 1842 in the South End, and the first Jewish cemetery in East Boston in 1849. In 1852, the congregation constructed a synagogue on Warren Street, modeled after Newport’s Touro Synagogue. Increasing membership prompted further moves: in 1863, to the Warrenton Street Universalist Church (now the Charles Playhouse) and in 1886, to the Union Park Street Church (now a Greek Orthodox Church) in the South End. In 1928, the congregation built its current temple center on Beacon Street in Brookline (1187 Beacon St., 617-277-6610).