"Somewhat tense here" was probably true of almost every moment +/- 25 years, "... but I think everything will proceed as per program" might suggest that the referenced tension was local, eg, a business deal, or distributing Bibles to the idolatrous heathen natives, or snagging a missionary or diplomat in marriage.
Googling the addressee {kathleen hand wilkes-barre PA} brought-up a directory of the DAR (Daughters of The American Revolution).
I do not think I will ever wrap my head around the idea that you could scribble transit instructions on a piece of mail, and that your wishes would be honored.
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http://www.chinastampsociety.org/Cheers,
/s/ ikeyPikey