Fairly local to me and use to attend every year along with the Superbike races when they ran there. It's not near as inexpensive as it use to be and now living with a medical condition that keeps me from going. My only advise is if you don't want to be standing on your feet the entire time take some kind of pitbike or scooter. The Mid-Ohio facility is pretty large and if you're interested in a lot of stuff swap meet, road racing, vintage MX, trials you will be putting in some miles for sure.
Plenty of videos on YouTube to show what it's all about.