I am a descendant of Harrison Branscomb. My Great great grandfather, Charles Alfred Alcorn married Nancy Elizabeth Branscom (Harrison's daughter) I would be interested in reading the letters you offered to email if it would not be too much trouble.
The "Fronia" you refer to might be Frona Twyford. Nancy Elizabeth remarried to George Twyford (sometime after 1886) after Charles Alcorn died in 1884. I have a Frona Twyford listed as a daughter. I haven't done much research there yet, but you may check my tree on ancestry to see if it helps.