Went there Saturday, it's easy to find, if your looking to go there!
I-74 west into Illinois, past the 3 major Danville exits, take exit 210 (Rt 150), turn left, and the Vermilion County fairgrounds is on the right (a no outlet street) about a half mile down Rt. 150.
Don't forget the hour time difference!

http://www.vermilioncountyspeedway.com/directions.htm