Im trying to do the same for van but im no where near as skilled... slowly trying to layer it on.
the bridge across the main straight has a support so I did some editing on an existing pole to try to make my own. Turned out ok but the real one is square and not round. Added a light to it that works with the race flags like all the others.
Im super happy right now because I just found the mother load of reference photos for the 2000 race. 413 photos in a zip so Ill download that after the little one finishes online learning.
For the lidar, Ill export the road mesh and follow all the proper things and then see if I can export the buildings from google as reference for heights etc. Would really like it to be as accurate as possible. What Im finding is that cleaning it all up... is a lot of work compared to building it the way you want and taking CSP into account while doing that. Im shoehorning in stuff and working with 9 textures for a single mesh and the textures are sometimes under 100kbs... In the end, a full scratchbuilt will look as good as your 3R as Im starting to get limited by the existing.