I purchased some old post cardsof WI churches, two of which had writing on the back; one was addressed to Mr. Ernest Beckwith, Rockefeller, Illinois, and it had "Greetings to you and Mrs. B." Photo front is a Bloomington Wis. church; the card was posted at Bloomington, year is blank; the signature on the back appears to be Leo B. or LWB.
The other card is addressed to "Miss Helen M. Beckwith, Evarts, KY," then diagnoally, in same handwriting, 'Black or Block Mt.Academy.' It says, "Hello Helen: am having my vacaton but am going back to Wheaton today. Was over to Tomah and got this card. HHJ." (Photo of Tomah Baptist Church, Tomah, WI on front). Year appears to be 1903. the zero is almost faded out.
(I'm not related and have no other info on people named...posted FYI).