was trying to work on this track when time,
it is in fact 90% complete and have been able before to drive it and reach the finish line
however now it went out of memory a few times almost before the end
already reduced grass etc., problems started when I started to add buildings (before the buildings I could drive the complete track), however also again reduced the buildings, before reducing the buildings back (I deleted about 20 buildings, not too much but cannot delete more then there is nothing left of the two decorative villages) I could not drive also for 1 minute before the out of memory message appeared.
another issue it has is that at high altitude the terrain becomes invariant to the car, on the track no problem, but when the track is left the car drops below the terrain
hopefully you have some tweaks and settings with which it can work
https://we.tl/t-n14FaPGesM