Every track I go to is different each time.
The tracks I see are from 120 to 150 feet ling and 50-70 feet wide.
Even the permanent tracks change configurations each time. Most tracks use old fire hoses to make the lanes. A track usually has an oval around the outside and on road is configured in the in field. The layout can be anything you want. Some are real technical and slow and some are more wind and sweeping. Go to different track websites and find what you like, try it and change it to find what works best for you.