Thank you for the link to the entire letter and the analysis, Cynic. One of the things that the letter writer did that is especially irritating is mix up their personal pronouns. First it's "we", then "I", and on and on. I think the letter was written quickly and the writer was most likely in a panic.
BOESP-thank you for the explanation about the phrases. WV is an area where a southern dialect is spoken; however, I am now learning that Patsy lived in quite a few different parts of the US (GA, MI, CO). I think you're right that her speech was affected, and she probably picked up idiomatic expressions and pronunciations from each of the places she in which she lived, which probably explains the "hither and yon" phrase.
One of the things that jumped out at me when I read the letter was the mention of how the "kidnappers" supposedly respect John's business. Another business mention in a letter from that home-ugh. If Patsy wrote that letter, then this is another example of how she wanted to have that identity associated with her-the wife of a successful businessperson.
I think you're correct in saying it was written in a panic. As to quickly, well, it's sort of a relative term. There was a practice note, and the final version was 2.5 pages, handwritten. I'm not sure how quickly that could be done.