Ahhh Ghostly Valley and great place to be. To get there You'll need to KILL ghosts. Ghost spawn in the Overworld and the Valley, they drop Ghost Aura. Get them and craft 9 of them into a Ghost Entrance. Now you are in the valley, be careful though, the Lord of Death has a fortress around, and he does not play. You will be needed armor, way better than diamond. JEI is recommended for crafting recipes.
