Upvote:5
It exists at least one fairly moderna doctoral thesis about the organization of the Swedish Post : Postgång på växlande villkor : det svenska postväsendets organisation under stormaktstiden (Magnus Linnarsson)
The sender and the receiver was expected to take the letter to the nearest "postmästare" pay for the delivery and to be prepared to have arrangement done to check with the "postmästare" if any letters is destined to them.
A richer merchant for example would have his servants check for mail daily. A noble man/officer living out of town would arrange that a servant comes depending on, multiple times a week. State employed people would for the state related correspondence use a self-franking exception (ie no mail tariffs for the king's own correspondence.)
The "postmästare" forwards mail and sends his/her own mail to the next postmästare. The "generalpostmästaren" in Stockholm was a hub for the mail while he/she had a fairly big but depending on period not so, complete control off who was a local "postmästare". One exception was the postmästare in Norrköping which was chosen by the now abdicated queen Christina.
Magnus Linnarssons disertation is also available from here: Postgång på växlande villkor : det svenska postväsendets organisation under stormaktstiden (via Lunds Universitet)
Magnus L discusses while it for the king could be useful to, to be able to repay a loan, let the lender run the post as his own business and so being able to reimburse himself from the profits (entreprenad) or in a more directly state run business there the profits (maybe smaller because the "generalpostmästaren" wasnt himself directly dependent on the profits and so the business was less well running) was directly transfered to the king's coffers.