The Mumford family of Pleasant Mount, Wayne County, PA are descendants from Jireh Mumford (a.k.a. Jirah Mumford) of Rhode Island and his wife Deborah Lillibridge. The information I posted is from a book by Raymond Sampson "The history of Starrucca" and his book "Starrucca Remembrances."
If you check out the link below: http://genforum.genealogy.com/mumford/
and search for "Jireh" "Jirah" or "Peleg" you will probably find descendants researching this same family line who may have information on your ancestors. There is a Florence Mumford who posted and is researching the Mumford family from that area.
I am not researching this family. I have the honor of living in a historic home once occupied by Warren W. Mumford and his family. I have met many Mumford descendants and they have been kind and shared stories with me about the Mumford family, which I am able to share with others researching this family.
I will forward your post to a wonderful person, I met who is researching the Kellogg-Mumford family of Pleasant Mount. She may be able to give you some clues to your John Wakeman Mumford.
Good Luck in your search!