The AASHTO and YARN roads are my favorites too. What I like about the YARN roads is their thickness so they don't look like a thin strip of film floating over the landscape. There are some vehicles that are offset a little bit and tend to sink into the road surface, but that I think is less of a visual problem than floating roads.
I've reskinned a couple of the YARN roads already. I found a nice cobblestone texture and made some cobblestone roads with sidewalks with this. I've also taken the plain grey asphalt road and reskinned it with a gravel and sand texture.
John
I agree with all of your points about the YARN system, John.
Interesting how you have re-skinned the roads. One of my current projects is YARN2, an update to the original YARN system to make it more prototypical and complete, in case you have not noticed (how ever unlikely that may be

). One thing that it will feature is multiple pavement textures for each road mesh, e. g. multiple shades of concrete and asphalt, plus brick and the like. I have not considered gravel, etc., roads for the standard smooth mesh, but I suppose that for gravel roads and the like, I could probably make a higher-poly mesh to make the sides of the road appear to not be so straight and smooth.
The reason for why the carz sink in to the YARN roads a little was discussed back in my thread on YARN2 (from what I remember--it may have actually been Maddy's YARN thread

), and it involves the Z-position of the mesh, combined with the "grounded" field in the config.txt file. In TRS2004, there are no issues like this, as all carz float approximately 0.40 meters above the road, which equals floating/hovering carz on YARN roads in TRS2004!

However, I will be making a fix on the road mesh for the YARN2 update that should hopefully cure the slightly-sunk car problem.
Regards.