Order of design

1. Define the game/simulation
2. Behind-the-scenes math
3. Loading art assets/world map
4. Pathfinding
5. Economics

Define the game/simulation:

World map simulation which simulates large-scale economic, resource, environmental, and day-to-day activity between cities, towns, and villages of various sizes in a medieval setting. Cities exchange resources between each other in order to grow, and cities form naturally based on needs of neighboring cities and the surrounding resources available.

Components of the game:

1. Cities Population of the city Demographics (approximate, details jobs/production) General info that determines what a city produces, what it consumes, and what it wants.

2. Nations Trade between cities Exchange of resources to make up for

http://crowdsimulation.blogspot.com/2013/06/creating-your-own-game-simulation.html

http://gamedev.tutsplus.com/tutorials/implementation/how-to-use-voronoi-diagrams-to-control-ai/

http://gamedev.tutsplus.com/tutorials/implementation/cave-levels-cellular-automata/

http://gamedev.tutsplus.com/tutorials/implementation/goal-based-vector-field-pathfinding/