Mystery at Dark Cedars

Edith Harper Lavell wrote the Mary Louise Gay series (3 books); the first of which is The Mystery of Dark Cedars, based around President Roosevelt's order to prevent the hoarding of gold during the Depression. Lavell authored two more famous series, one featuring girl pilot Linda Carlton (5 books) and the Girl Scouts series (10 books). Unlike many series authors, Edith Lavell was an actual person, not a house name.