When you first get it, only Presto's Edge is available. To get each place to show up on your map you must find the flag for it. The flag looks like a red triangle on a gold pole, the pictures below are actual size. It's easy to find them and they disappear once you've clicked on it. After you've collected a rooms flag you get 25 coins and you can use the map to travel there. This will definitely save you time instead of walking!
Some of the areas in Dizzywood, such as the Jaguar Temple, The Crystal Catacombs, Elder Vein Mines, and Skytown Skate Park are not available from the map, probably because they require special powers or items to get there.
Note: Farthling's Meadow is no longer availible.