I'm looking for systems similar to Kingmaker (where the PCs rule and expand a kingdom), except I want it to be much more realistic and complex.
A few examples of what I mean:
- Instead of 'Building Points', actual resources are required (ex: wood, stone, ores, etc.)
- Instead of the king and his most important men exploring and traveling dangerously, they'd send other people.
- Trading to be much more emphasized and complex (tariffs, specific trading goods to import and export).
- Diplomacy to allow for embassies, so towns can work together (end up getting free trade agreements, maybe other benefits).
Best Answer
Adventurer Conqueror King address many of the same topics as Paizo's Kingmaker. Also the treasure generation system has been aligned with economic assumptions of the domain system. The rules address mercantile ventures, and building not only of castles but other types of holdings. The different elements are defined in natural terms of gold pieces, days of constructs, number of personnel rather than a abstract system of points.
The rulebook can be purchased from here.
More narrow in focus are Columbia Games Harnmanor and Pilot's Almanac (if you can find it). While having detailed mechanics both are highly playable. If you are familiar with Classic Traveller they are of similar complexity. The individual supplements also function well as a standalone rules subsystem. Harn is a low fantasy medieval setting so it supplement are usable with any fantasy RPGs that has a fantasy medieval implied setting like Pathfinder or Dungeons & Dragons.