Ok, so here is an updated version. Overall , I am pretty much satisfied with the road, but will fine tune a few things that aren't perfect enough yet.
Just FYI: this is still 100% compliant with the Free Edition limitations of Terragen 2, except that larger render size.
The sky is ok-ish. It's not the one I was working on earlier and then failed - this is another one, an overcast sky this time around.
After the road fine tuning, I will attend to the surrounding terrain. POV may change also, but I believe I will keep it relatively close to the ground. Which is a challenge in itself, as it's much harder to make things look photo real on close up.
Anyway, I will keep at it.