The information below is provided for historical reference.
Mickey's Toontown last day of operation was February 11, 2011, after which it closed to make room for the Storybook Circus portion of the Fantasyland Expansion announced in 2009.
Before closing, Toontown held most of the formal character greeting areas in the Magic Kingdom, including dedicated areas for Disney princesses and Mickey Mouse, as well as a play area and a kid-friendly miniature roller coaster.
The Barnstormer lives on as the same roller coaster, but with an updated theme. The princesses ultimately moved to Princess Fairytale Hall, but character greetings persist in this area at Pete's Silly Sideshow.
The design objective of Toontown is to immerse you into a cartoon world. To that end, Toontown's architecture uses a trick from animation called "squash and stretch". This effect keeps the volume of the structure constant while it is "squashed and stretched" in seemingly unnatural ways. Imagine blowing up a long thin balloon and squeezing (or squashing) one end. The other end stretches and gets much larger. None of Toontown's buildings have straight lines and they are painted in super bright colors.
Due to Toontown Fair's heritage, the layout doesn't follow any of the rules laid out in the other lands. There is no "wienie", which is a significant attraction that draws you from afar. There is just a sign. There is no strong center. In urban design, a strong center is piece of common land that transforms the area into an outdoor room. A strong center leads to activity pockets at the edges of the area. The life of a public area is activated by both a strong element and the edges. Toontown Fair is just a corridor leading to a train station that does not support the overall theme. And no, the statue of Cornelius Coot doesn't count.