This is the first of five appearances Harry Harvey makes in this series, each time playing the role of a different character. In the 1960s, both he and June Lockhart, would appear again, although not in any scenes together, in Return from Outer Space (1965) from the sci-fi TV series Lost in Space (1965).
This is the first of four appearances William Henry makes in the series, each time playing a different character.
The Sugar Maple trees (Acer saccharum) that Uncle Petrie spots grow primarily in the New England region of the U.S. and in parts of Canada; they are not known to survive or thrive in other parts of the U.S., logically making Uncle Petrie's find either a case of mistaken identity or placing the Martin farm somewhere in New England.