I've tried some of these, and others I've already done when I spend time jumping around Regalia, and in my opinion, slums are the best. They're designed to be crowded, with things on the side of paths and walkways alongside the side of the buildings, and the narrow gaps between houses. I, myself, adore the slums, which is visible by me jumping around and also that I could tell you that most bases are 14-16x20-24 blocks. Regalia poses good fun, and I do jump around it a lot, but slums is where I prefer. Asides from that, this is really cool- and good fun to watch.