It's worth blocking things out to give you an idea of what you are looking at. I come from the UK so he roads here are all right hand drive. Practically every where else has left hand drive (Bloody Americans :) not to mention the Germans and the French) so road markings on junctions are really obviously different. Everything else should be fine. So I will need to lots of junctions or things will look wrong. I will start with doing left hand drive versions. Fortunately the UK has not been the scene of any major land battles whilst we have had metaled roads. Might be a problem if I want to do VBCW.
This is a sample of the plan. I am currently thinking about how to work out the practicalities. Beveled terrain usually looks better but there is a part of me that wants to use this for something a bit more integrated, maybe putting magnets in it and finding some steel sheets to attach to the board. If I do that the Y junctions may be redundant.
As a addendum, I've added a few dirt tracks. This will probably be the first project as I am guessing it this will be the easiest to complete. Just work out the curves.