Well you have picked a very tough idea to map. The nature of stacked buildings on top of each other will be very tricky to do from the top. I have been making a few dwarven maps for my own campaign, and I decided that there would be virtually no rounded shapes, everything being square or octagonal. So I think your thinking is about right. You can also keep the color choices to just greys and browns, maybe some dark greens for water. Good luck with your map.