Leaving military service, Phelps returned to Brattleboro, Vermont where he became President of the Vermont Teacher's Association from 1865 to 1885. He lived in Brattleboro until 1883, when he married Anna Bardwell Davis. They moved back to his birthplace, Guilford, Vermont. He traveled across Europe and the United States, developing a reputation as a scholar and linguist. He authored "Phelps Elementary Reader for Public Schools Good Behavior" (1876), and translated from the French three books: the Lucien de la Hodde's "The Cradle of Rebellions: A History of the Secret Societies of France", "The Island of Madagascar: A Sketch, Descriptive and Historical" (1885), and "The Fables" of Florian (1888). He became very active in the Vermont Historical Society.