Yes.
While you are on one quite big terrain, the otheres which are far away (you have to travel per ship) just are (with everything on those terrains) passable and invisible until you reached a surtain distance.
In that way you could make a really big world with alot of "countries" and towns to discover.

The questin is, how big can a terrain be without killing fps and nexus?
5 times as big as that terrain from the car demo would be great!