It's along the ravine behind the farm. It goes the world Laedis, Artecia City. But from Artecia (city in Laedis) you can fly down to "Under World Port" (another city in Laedis) and take air ships to other places.
You can find the maps to the worlds here in the Dragon's Prophet Wiki. (info also good for Savage Hunt) Along with other important information for beginners.