[reaperducer]

In books, probably. But this was before the web, so I don't know if there are any authoritative web sites about it. You might check the old late 1970's and early 1980's computer magazines on archive.org.

A large part of the delay is that messages were transmitted in a store-and-forward scheme (often via uucp). And most machines didn't send messages more than once a day because connectivity was expensive and measured in dollars per minute. And when they did connect to the next machine, it was usually not a very long hop. Sometimes one part of a campus to another. Or to a computer in the next town.

I really don't know exactly how the messages crossed oceans. Satellite transmission would have been unthinkable. My guess is that eventually they hit some big east coast computing center like MIT or BBN and went via undersea cable, but that's speculation.

I ran a node of one of the pre-intenet networks. Like most of the other nodes, it was connected via 150 or 300 baud dialup modem. Later there were a few 1200's, but they were rare.

My node was important because it was oddly located so that it could span two states and two area codes without incurring toll charges. That made it very busy, so the early morning (2am) message transfer sometimes took a couple of hours.

I tried to write a couple of articles about the old American dialup networks on Wikipedia once, but someone in another country deleted them saying they didn't exist because he'd never heard of it and if there was no web site to link to as reference it didn't happen. I stopped contributing to Wikipedia after that.