fascinating letter, startingover.
Lots of businessmen carried a portable typewriter with them on the train for catching up on correspondence. Undoubtedly Macmillan wrote this while travelling.
He was well known across WV, Ohio, and Ky. I once knew a brother (now deceased of course) who had known Macmillan and had him stay at his house when he visited their area in the '40's and early '50s. I think Macmillan lived into the '60's.
It's curious how the railroad-era towns like Brandonburg WV and Crooksville Ohio which became nearly ghost towns once the railroad passenger traffic pulled out.