Go to the high tool under terraining, which looks lilke a blue hill. Once there, I used the raise tool, to make a large hill. Then I used the uniform tool to create what you see in my pic, flattens the top, and because the shape of the brush, its a square, I then got the smooth tool, and went on the right side and tapped the button a few times (Pretty sensitive) Creating a ramp. I then used the tile for the cliff part, so it looks like a cliff. Finally I used the pathing tool to make it unwalkable. I told you before, stop being so closed minded xD, you can improvise and do it this way if you wanted, you can do this exactly how you want, it would just take you longer because you have to design your own cliffs.