The map could be generated with several large independent lakes that were not connected. Boats could be used to cross these large rivers to settlements on the other side or to shorten a journey. This could be an interesting way to generate the world now that horses are so predominate, though it would make the world very dreary and unnoticeable, since rivers are what I usually use as landmarks.
I think back to really old haven, even though I didn't play.
World 1 map (large image):
World 2 (I think) map (large image):