Yesterday I mentioned the presence of goldenrod in Maud Hart Lovelace's first novel, "The Black Angels". Goldenrod, as I said then, is a recurring element in the author's "Betsy-Tacy" books.
Now that I've read further, I've found other familiar items.
The "Cat Duet", which was introduced in "Betsy and Tacy Go Over The Big Hill"
Alex, in "The Black Angels", and Uncle Keith, in the "Betsy-Tacy" books, were both based on MHL's Uncle Frank, who left home to go onstage because of an overly-strict stepfather.
Also mentioned in "The Black Angels" are:
Fried potatoes. Remember how Mrs. Ray was always frying potatoes?
A pill-box with hair in it. THAT made me chuckle, remembering the pill-boxes in the "Red Hair, Yellow Hair, and Brown" chapter in "Betsy-Tacy and Tib".