I went off and did some research projects on Geometry Nodes in Blender, and I discovered some things and made some useful node trees. I haven't figured out how to do everything, but I did figure out two things: how to generate a convincing terrain mesh and attach it to the track, and how to do a separate physics mesh that meets properly with the edge of the track.
All this means two things:
1. The grass has been expanded out to fill the entire area of laserscan data that I exported from CloudCompare into Blender. This means you'll be able to drive around with less fear of falling off the track.
2. The track now has a separate physics and graphics mesh for the track surface. This means that the track should have... more "accurate" bumps. Or maybe "precise" is the right word. Also, the smoothing has been reset-- I tried to match it somewhat to v0.1's level, but since they differ so much in resolution, it's hard to tell without thorough testing, which I hope you guys will provide. For those who care, the physics mesh's longitudinal resolution is roughly the same as the average distance between points of the aerial laserscan data.
This update does NOT contain the pit area mesh, as shown in the discussion section. I won't have to completely redo it, but I need to find a different way of "meshing" it.