I read this book in the 1960s but I have the impression that it was published somewhat earlier. It was what we called a “chapter book.” What I remember is that the girl’s father was a locks keeper, and she used to walk along the towpath with barges or boats.
Stump the Bookseller
New format, same book stumper solving.
Tune for a Towpath by Jane Flory
Possibly “Houseboat Girl” by Lois Lenski?