Here’s a first working prototype of DynamicTerrain based Map+Terrain generator : Test Babylon Terrain Road 2
The map is randomly generated with a Perlin noise each run and a road is then “built” (the road curve radius is a bit randomly value, well the road path itselft is not for now randomly generated). The map is modified according to the road way : hills are truncated or polished.
Try to fly at the lowest altitude just over the road 
Next step : add trees or houses… well, random instances
Did you ever add LOD chunking and T-Junctions?
https://www.babylonjs-playground.com/#f00M0U#39
This prototype needs lots of optimisations. But most of the footwork is done.
I don’t use LOD in this example. But when using it, I just use the simple mechanism one from the DynamicTerrain.
https://www.babylonjs-playground.com/#I9SC1Q
Whoopsies here is the correct one with real T-Junctions.
like it…You could add a bit of fog to hide the way the terrain pops in the distance
yep
all this is planned… just a prototype for now
instances to be added first
then effects
Very Nice 
Work still in progress and buggy
http://jerome.bousquie.fr/BJS/test/terrainInstancesRoad.html
now with instances and fog …
Try to keep just above the road
Rahh! excellent buddy!
It looks awesome. The rotation sensitivity is too high for mobile. I rotated the camera and then I lost the road 
May be Lock the camera movement to look straight at road and allow only small rotation just like neck movement… . Like driving toward sunset