I think you're on the right track, and the world map analogy is apt. Often a world map is simply a rough outline of what will appear here, once the player accesses that location the finals are put into place. In your case you can determine that these are the types of people who would be here, and once the area is accessed the details are put into place. Since you mentioned DF - the DF world map doesn't even know what minerals will be in place when you embark, only the likelihood. Once you embark it may even turn out that some of the promised goods aren't there at all.
I think the next step would be calculating what has happened since last the player visited this location, rather than having events occur all the time. If you would prefer for actions to carry over into the portion of the world that the player is in, this shouldn't be too much of a drain because we're talking about a small subset of all the actions that could have taken place outside of the player's portion of the world.
If the player is gone from a section of the world long enough (the player went from one side of a continent to the other, and has been there for half of a year, lets say) you can update the portions he's left with more specific generalities. Where as before your generalities might have said bandits are 3 times as likely to patrol this area, you might now have your generality changed to Tom The Dreaded is 5 times as likely to be here as other areas, and so is his Dreaded Tom Gang. Other bandit groups are twice as likely to be here.
While the player was far away, on the western portion of the continent, perhaps some random dice roll might have determined a bandit robbed a silk caravan headed to the main trade hub on the eastern side of the continent, and another roll assigns the crime to Tom the Dreaded. The merchant who stands before you far to the west has no patience for your insinuations as to the price of silk, for troubles in the east have caused a shortage of supply.
If the player returns to the original area a generation of it might go something like:
Is Tom the Dreaded here? Yes
Is Tom the Dreaded's Gang Here? Most are ranging, he has a reduced force
Are other bandit groups here? Yes.
Are any events occurring between them? Another Bandit Group is in battle with Tom the Dreaded and his gang