You've probably seen this book on a few shelves and in passing on Twitter. I took the time to map out all the locations. Have you read it? Anything stick out to you? Don't get thrown off by the title "Secret", it's a book series by Reedy Press. Most of this is either common knowledge or just less known, not necessarily a secret.
Minor quibble, but he has "Goose Hollow" listed as a Croatian neighborhood, but it was really a Lithuanian neighborhood, roughly bounded by So. 33rd St, So. 36th St., "T"St. and "V" St.. The name comes from the small barnyard animals (geese, ducks, etc.) that the "babushka's" used to raise in their back yards. I grew up within quacking distance of this neighborhood.