I also made an extension for Oakes Field that has GrassFX, RainFX, Light Bounce, some shader adjustments and some basic lights for night driving. It looks a little better, but the track is quite dated so it's hard to get it to look amazing.
Create a folder called "extension" in Content>Tracks>oakes_field - rename the attachment to *.zip and extract the ext_config.ini to the extension folder.
1. Download the attachment in this post
2. Rename oakes_field_extension.zip.txt to oakes_field_extension.zip (just delete the .txt at the end)
3. Open zip file
4. drop extension folder in the zip file into oakes_field track folder