Just a proposal.
|First, I place the textures on the path of the road, using a "straight" road texture along the grid, and "fork" road textures across the grid.|
|Then, I rotate the textures in order to form a continuous road.|
|Finally, I move the nodes according to the shape I want to give to the road. Note that, at the same time, I move the nearby nodes to form the hills around the road. In moutaineous country, roads are mostly in the valleys.|
|My observation is that the DEM elevations used are not accurate; all mountain tops are too low, and valleys, not deep enough. So, I do a lot of elevation adjustment, especially along the roads, which need only moderate elevation difference.|
I think some may be afraid to move nodes around and change their elevations. Don't, because they are not that accurate to start with. Rather, use these to shape the world you want to create.