Agreed. That's a very nice painted-feel map. As for towns and cities, either a daub of paint (maybe in red, or yellow for contrast) or a rough inky sketch that looks as if it has been added after the rest of the map has dried might work? The first would be relatively easy and would keep in theme but might not be the look you want. The second would be harder to achieve, but might be worth the effort. Maybe consider doing the towns in an oxblood or sepia colour. As long as they don't fade into the background too much that might work nicely. Just some thoughts.

Chris