Just crank up the resolution of the terrain meshes. I notice that Vue automatically creates a pretty high mesh with a lot of polygons. A lot of people then flatten their meshes to indicate fairly flat ground, or a path or something, but they don't reduce the "resolution" of the meshes, even when they are using materials with 'noise" to generate the acutal surface appearance. So, many people's scenes have an unnecessarily high polygon count (red numbers). It follows that you could just go in and crank up the mesh resolution without changing any real features of your scene. Mesh resolution probably is the single greatest source of polygons in anybody's scene.