I would be willing to make barely accurate cave drawings for any caves you may implement.
Also, I think the three surrounding areas should be random and should appear in the four squares immediately adjacent to the start area, obviously randomly configured.
Lastly, and I know this is insane, but isn't the Bionicle series set in the distant past? Maybe they came before Earth came, on the Old Earth, and invented space travel to wait for a New Earth to appear for them to inhabit because they found that the predecessor to our solar system was gonna explode, and when it did, they lived in the cave I suggested and died there and you can find Lego Bionicle parts in the cave as plot objects! Okay, I admit it's stupid.