Well the population density dropped significantly in the middle ages - check for example: This page 72 it mentions some central-european cities like Augsburg or Salzburg with densities of around 50 per ha thus 5000 per km˛. Would need 7 km˛ for 35.000 which is about the usable landarea of that topography...

I think my numbers are pretty solid and how many buildings actually fit the map will be determined when it is done.