When it comes to how many cities you need, you could have a single large city with many towns, depending on the government type it can be farely easy to keep the populous relatively happy and working, but if you want [control] you will need a larger military, which means several small cities and a capital that demands the first son of every family to serve a time in the military. while not at war this military force protects and keeps these cities in order, as well as the farm land that is needed for the civilization to thrive. which would also aid in the appearance of being chased by a central government. small cities just large enough to hide in, but not large enough to disappear in. a metropolice is the perfect place to hide amungst the people, this set up makes that difficult.