There is a place but it is far away, after entering the laboratory and defeating the "guardian" so to speak, you open the door and go towards some blue stairs at the bottom and at the top to the right, there you will come out to the surfaces if you continue on the left you will see that the ground begins to turn into dirt and is a cliff. There is a good place because you put up a few defenses where you came from and since the tribals do not teleport to your base, they will come by no matter what.