I think you should expand this. So far, as it is, there is no real room for terrain. My advice to you is to expand the borders
and add more terrain.
As for the borders, you should try to make them look like a piece of the terrain for consistency. Perhaps disguise them
as a cliff/mountain face. Having a box that outlines your build never looks good and ruins immersion.
Edit: Also, make the image a tad smaller. Page stretch is killing me..