I expiremented with creating the track with Gmax about a month ago, but couldnt do anything really, because of my lack of knowlege of Gmax.
I am thinking of picking it back up this weekend, because now all of that drivabe surfaces for FS seems so simple now. I could release what is in those screenshots as a version 0.5 or something if you want, because all of that is just one .bgl for FSX cuz its all defalt objects.
I do plan to create a pretty detailed version that is exactly (or as close as I can get) to the real track. We do have banked turns here in real life so it should make the turning a bit easier, since it is only a 1/4 mile. I do have all of the track measurements and banking angles, and I plan to start work on it again after I get the challenger ready to export, and this other scenery I am working on (which is all done just need to figure out how to get it imported into FSX)
Wow I just typed alot

EDIT:
It's funny I was just reading the old replies in this thread, and what you were saying about the drivable surfaces and stuff for the walls, when you first posted I had no clue what you were talking about at all, but now that I have been working with Gmax for a few months straight I know exactly what you are saying, and I will try that