Adventure Paths (APs) come with a freely downloadable player's guide that details a lot of things about the setting of the AP, including mechanical suggestions such as which prestige classes or class features are the most useful and a frontload of character knowledge about the place where the AP will start.

In the Player's Guide to the Giantslayer AP, for instance, we get the main locations, main NPCs and main history facts about Trunau - but it is suggested that at least one character comes from Trunau, and the others might come from surrounding lands.

My players want to play a party of dwarves, so the guide suggests they come from Janderhoff (across the Mindspin Mountains, in Varisia), Glimmerhold (to the south of Janderhoff, in Nidal), or Kraggodan (further south, in the southern part of Nirmathas).

Given that there's only a handful of dwarves in Trunau and that some are important NPCs, I guess that maybe one of the Trunau dwarves is a PC and the others might be clanmates visiting (or some other excuse we will concoct during session 0). So, their knowledge about Trunau, the Hold of Belkzen and the background that informs the actions of enemy NPCs might vary because of two factors:

  1. where they come from, because people from Trunau will know more things abut Trunau and about Belkzen
  2. their knowledge: history/nobilty modifiers

My aim is to provide each player a summary of useful informations and trivia that their character knows, in order to both help them create a character that feels like it belongs to the setting and to avoid the "you suddenly remember that" mechanic of knowledge skill checks.

What's the best way to decide who knows what?

By best I mean the one that will make the most sense for the setting and the characters.