>>36143505You don't necessarily have to do anything with the bottom right. Although you could use it to make the path to the cave more natural, you could include a NPC house (like the ones on Route 2), or even just have a small area for a future side quest event.
If you really wanted to get wild, you could leave it mostly as-is and add a "door" to a forest map. like Berry Forest for example. It could even just be an optional area for later on in the game to help with Pokemon distribution.
