I know I’m late to the party but I have recently been obsessed with this same topic. GURPS Fantasy does cover this topic as well and, similar to WFRP, splits settlements into isolates, villages, market villages, towns, and cities.
In general tough I look at it from the angle of “where does the food come from?” Which, depending on if the mode of transport consumes the food too (e.g. grain and draft animals), may only be a few days travel from the city; unless there are rivers etc. that can help move goods further easier.



It’s a speedrun 🙃