If you want a more controlable terrain, use a grid in the vertex modeler.
Start out with a fairly low number of quads and use the magnet tool to raise the grid into a basic terrain. (Hold down ctrl to limit the magnet to the z- direction.
Then you can subdivide the mesh & convert it to vertexes to make more detail.
Here is a quick mountain with a cave and a road done in the vertex modeler.
Note that my shading domains on the road need some work, but it was only a test.
