What would be the best way to create 2x25km landscape?

Hi. I would like to make a long but narrow landscape. What would be the best way to do it? Player should be able to go from start to end. Is level streaming an option?

Yes, level streaming is a must. Also, it would be wise if you could make few cut scenes here and there and load new map during the cut scene. It would be beneficial if you could share more info so we can analyse all possible approaches to this.

Imagine a 25x2km landscape, with grass, trees and various props for the player to explore freely