huge vista, almost none of it used in gameplay. any optimization help?

the level is large enough that it extends just a bit beyond default draw range in the editor. there are also some light building errors because of the size.
under Source, I would have downsized the unplayable parts and placed them in a skybox.
is there any way I could optimize it in UE4, such as static, high LOD around the play area, and low LOD in the distance, or a skybox-like feature?

any help would be very much appreciated.

First your level should be streaming. If you can’t see it the computer shouldn’t load it… at all. If you’re not there, the computer shouldn’t load it… at all. I know this is happening by default in many cases but you still need level streaming volumes to help out. For instance, in Borderlands, there’s a generic background and objects that the player interacts with don’t pop into view until the player is close enough to actually be able to see them. This is level streaming. There’s a volume that says ‘Don’t load what’s inside this until the player is close to it!’ Same goes for lighting volumes. You need a lighting volume (or volumes) that’s large enough to cover your world, but unless your player can fly you don’t need your computer to compute lighting everywhere. Just as far as the player will go in a given direction. Otherwise UE4 will calculate lighting on the underside of your map as well. LOL