Fits over here too.
I have a book with letters from Danes in USA written end of 1800 and beginning of 1900. Sometimes the writer thanks for the letter of...date.
Have the feeling it took about 2 weeks to get to Denmark.
That is what it also takes now by air.
According to Pear´ Calender 1914
Mails from America
Day of sailing Wednesday - Amrican Line - due in London - Wednesday
The others also took a week.
I know that a letter mailed in N:Y in the 60ies arrived in Sweden Wednesday - as rule - when one answered the same day it could be in N.Y again Saturday.
Now an e-mail takes a minute - and the answer months....