Update: I'm currently at the point where I now have all of the track surface modelled and textured and I'm a good way through modelling the kerbs. I've also started to block out buildings and fences and it's at a point where I can test everything in Assetto Corsa.
The track already feels really fun to drive so I can't wait to make some more progress soon.
If you'd like to get early access, sign up as a Patreon and you'll soon be able to try this track out for yourself!