This looks exactly like what I'm thinking of, for example:
The theme of my neighborhood walking tours is to unite us with the past through history, architecture, pictures & stories. We explore Manhattan's many neighborhoods through its unique landmark skyscrapers, turn of the century mansions, brownstones, clubs, public building & historic districts. Many New York City or national landmarks with historic (Romanesque, Classical, Baroque, Queen Ann, Gothic, Renaissance) or anti-historic (Art Nouveau, Art Deco, Modern, Post Modern) styles of architecture are included. My specialized tours cross neighborhood boundaries and focus on various other themes such as: gargoyles, Jewish history, Irish history, Italian history and outdoor art / sculpture .
Actually there's plenty of similar sites.
This one is a much more sophisticated web site -- for Big Onion Walking Tours:
There's dozens of appetizing tours, including one of Greenwich Village:
Stroll through New York's unique and legendary home to artists, writers and radicals, with a special emphasis on the history and architecture of this neighborhood. Stops include: the Jefferson Market Courthouse, the "hanging elm", the Stonewall Inn, and sites associated with Stanford White, Aaron Burr, Edith Wharton, e.e. cummings, and Thomas Paine.
That might be a little "touristy" (rather than literary/historica/academic), but maybe not.
There's a page of links to all sorts of walking tours:
There's a "Foods of New York" series of tours!
It goes on. And on and on. The research will be great fun for me. Maybe when I'm in NYC next month I'll take a tour myself, to check out one that looks promising.
Sudden uncharacteristic whine: I want to be rich and retired with all the time in the world to do this stuff in every city on the planet.