Of course, you will also want to visit the Wicked Witch's castle, and be sure to wander the various nearby paths, particularly the one leading downhill towards the water:
To get to Munchkinland simply follow the signs and the yellow brick road.
It is worth heading off the beaten path in The Magic of Oz. With a mesh build and its comparatively low land impact, the builders were able to hide all sorts of interesting things in odd corners. Enjoy!