i had the same problem with the north! just go north of (or above) the museum, and walk along the trees, you'll find the entrance to the north area (its centered to the museum, if that makes sense?) as for the inventory, i dont know if you can select items within it, just because i dont think its ever needed in the game (if you have the relevant item in your inventory, then just interacting with things should get the intended result, at least in my experience!)