Looks promising!
At the moment, you don't seem to care about the textures.
I prefer to include tiled textures from the beginning, at least placeholders, to see the tiling.
I use already textured model pieces and stitch them together to avoid seams, because I think it is less work with the uv-mapping.
But, it depends on the landscapes, maybe, your environment won't take profit from my method. I don't know.

Keep up the work!