The spread of knowledge in a large game world

These days we have television, and news. But in a late bronze age world there are no broadcast media. News spreads by word of mouth. If non-player characters are to respond effectively to events in the world, knowledge has to spread.
How to model this?
Worlds and Flats
Of Compartmented Worlds
Playing The Witcher has got me thinking again about an algorithm for rendering a world which I first thought of twenty-five years ago. Then, it was a hack for dealing with the fact that the computers of the day didn't have much memory or horsepower. Now, it's a hack for dealing with the fact that — when considered against the complexity of a world — the computers of today still don't have enough memory and horsepower. Mind you, today I'm contemplating photorealistic scenes, whereas then simple line and wash would have been good enough, but...
The algorithm for rendering I'll call 'flats'. But before we get to discussing flats, lets discuss worlds. The world of The Witcher (and other games based on the Aurora engine) is composed of areas. One area is loaded into memory at a time; when the player reaches an area boundary, the area is unloaded in toto, and the next area loaded, also in toto. The result is a noticeable interruption in game play. There's also, normally, a noticeable visual disjunction at the boundary; the new area uses a different 'tileset', which is to say, set of bits of scenery. When you look across a boundary, the scenery often appears different from what you find when you cross the boundary and arrive at the other side.
The Witcher: Story telling of a high order

This isn't, by any means, a final review of The Witcher. I've played it fairly intensely over three weeks, and am only into the fourth chapter. Which is great, because there is more to come.
But, what do I think of the show so far?
The best wee act of hegemony in the world
We're all familiar with Jack McConnell's slogan for Scotland's airports. We're all familiar with the incoming nationalist government's dislike of it, and rapid deletion of it. But Jack McConnell must be laughing up his sleeve; we, the nationalists, have missed a trick — badly — and Jack has achieved all he set out to achieve.
Because we didn't challenge the truth of the slogan; we didn't notice that it needed to be challenged. So the idea — the meme — the hegemonic masterstroke that McConnell set out to achieve has been achieved. We have cast our national debate in terms of being a small nation. If you went out in any street in Scotland and asked ten passers by whether Scotland was a big country, a middle sized country, or a small country, all ten would agree, Scotland is 'wee'.
We like the notion. It's romantic, the small band against the world. Our national myth — our stories of Wallace and Bruce are cast as the brave few against the might of a much more powerful hostile world. And so we let it pass unchallenged, and thus give an unnecessary gift to the unionists. Like James the Fourth at Flodden Field, we march down off the strong hill to face our opponents on their territory.
Of Size, and Governance
If you set out from Langholm, in Eskdale, and drive in a car to Drummore in the Rhinns of Galloway, you will drive 119 miles, and — according to Google's mapping system — it will take you 4 hours and eight minutes. If you didn't fancy Drummore, you could get to Stafford, in Staffordshire, in one minute less; or Dunkeld, in Perthshire, in five minutes less.
From Drummore, driving by road (and taking ferries where appropriate), you could get to Dunoon in Argyle or Dunblane in Perthshire quicker than you could get to Langholm. Even with the ferry, getting to Dundalk in the Republic or Ireland would only take 21 minutes longer.
So what's amazing or shocking about that?