The logical implementation seems fairly easy to imagine to me.
You do ant-like pheromone tracking for movement by all peasants of the world. (Each cell keeps a tracker, which gets incremented by passing peasants and decays over time).
Upon sufficient pheromone build up, your walking tile upgrades. Perhaps in the form of grass -> well-trodden -> dirt road -> gravel road -> stone road. Simple model of decay would be to simply downgrade back down the list. More complex might be that stone/gravel degrade into some special state to maintain permanence (dirt roads goes back to grass, but stone roads turn to grassy stone or whatever).
Your peasant/wagon/etc pathfind accordingly, getting speedboosts (or losses) by road type — and in your example, by road type + local weather (modeled separately)
You could also have different pheremone types producing different artifacts. Human pheremone only produces dirt roads at max, but wagon and tamed horse pheremone jump from grass->road with sufficient buildup. Wild animals only build up to well-trodden paths.
You do ant-like pheromone tracking for movement by all peasants of the world. (Each cell keeps a tracker, which gets incremented by passing peasants and decays over time).
Upon sufficient pheromone build up, your walking tile upgrades. Perhaps in the form of grass -> well-trodden -> dirt road -> gravel road -> stone road. Simple model of decay would be to simply downgrade back down the list. More complex might be that stone/gravel degrade into some special state to maintain permanence (dirt roads goes back to grass, but stone roads turn to grassy stone or whatever).
Your peasant/wagon/etc pathfind accordingly, getting speedboosts (or losses) by road type — and in your example, by road type + local weather (modeled separately)
You could also have different pheremone types producing different artifacts. Human pheremone only produces dirt roads at max, but wagon and tamed horse pheremone jump from grass->road with sufficient buildup. Wild animals only build up to well-trodden paths.