Good question. The Black Hart can lead you to location 7 and the Green Knight can lead you to location 1.
Originally, attempting to follow either gave you a modifier to the roll, though it looks like I accidentally deleted that from the final version of the Green Knight as a adjusting for space. It could be added in easily enough in play, paralleling the Hart--when you attempt to follow the Green Knight out of a location, subtract one from the next exploration roll; if you have already explored locations 2–6, then he takes you directly to location 1.