Make forts/cities not always closed to outsiders, but make parts enter-able to merchants to trade between cities, for economy and travelers to thrive.
Like in medieval cities and tv series and other medieval games, cities are always full of merchants, shoppers with food, armoury, markets etcetera, and economy between cities
to make profit by logistic to far destination of valueable materials being present for example only in one part of map. But definitelly being crafting game, peasants, farmers would benefit being able automatically or by person to sell the vegetables/trees/food/products they grow, plant, produce to sell. And merchant cars would benefit like transport tycoon, or truck simulator for distributing the goods.