The Book of Dow has a Roscoe Dow that doesn't really match your facts, but since it is mentions a Frederick Fetch, and also has an Ida, I am passing this info along in case it provides you a clue. It has:
Alroy C Dow shoemaker of Seabrook d June 9 1902; m Mch 22, 1884, Ida May Felch b 1869, dau of Frederick F and Nancy L of Seabrook. Children: Roscoe F b July 30, 1884; Charlotte b Apr 28,1898.
Roscoe F. Dow m Amesbury May 11 1903, Alberta Rines, ae 22, dau of Albert and Fannie (Davis). Child: ____son b Newburyport Feb 6 1905