How does the mail work in your world?
Granted, this doesn’t seem to come up as a big thing in most fantastic fiction. The thrill of, “will our heroes make it in time?” is totally lost if the bad guys win because of a minion’s email. Yet some of the oldest written documents we have are letters, business and administrative, so you ought to consider how long-range communication works in your world. Or if it doesn’t, why not? Because people have always wanted news from far-off places, and gone to great lengths to get it. Witness the fact that Galileo’s telescope was used not just to observe the skies and start theological brawls with the Inquisition, but for an early form of insider trading. By spotting sails far away, they could tell which ships had made it back from the Indies hours before anyone else, and buy shares and place bets in advance.
In a similar vein people reading accounts of how the Greek oracles of Apollo seemed to have uncanny knowledge of far-off places and events have looked askance at the fact such temples were also known for keeping white doves. Possible messenger pigeons, anyone?
This is also part of what makes Dracula so effective as a written novel. It’s told through journal entries, letters that may or may not have been received in time, newspaper clippings, and even train schedules. The vampire may be rich, supernatural, and a definite Out of Context problem for our Victorian heroes, but through communications, our heroes unite and finally defeat the bloodsucking menace.
(Well, communications, a stake, and a Bowie knife. Gotta love Texans. Even if Stoker had no idea what they really sound like.)
Pigeon mail, foot messengers, Pony Express, radio, telegraph – the tech level of your world may change how communications travel, but they will travel. The question is whether you need to just get information transmitted, or info and a physical object. Radio, telepathy, and so on are fine if you just need a verbal account of what’s going on. But if you need tests run on, say, a blood sample – there’s a good reason one London hospital keeps pigeon handlers employed. The closest analysis lab is on the other side of a river with only a few extremely congested bridges. The birds can take a vial over in minutes, while a truck might take half the day. When it comes to emergency medicine, speed matters.
Pigeon sample delivery is a niche situation, yes. But little niches like that make for neat stories, and intriguing characters that will draw readers back again and again.
And then, of course, there’s always the Mysterious Package Delivery that starts an adventure….