Would recommend for older kids unless you kid loves loud noise to go to sleep. Good amount of food to buy there. And other random stuff. If have younger kids or even older ones you don't trust, keep an eye on them. A lot of teenagers hang out in various spots doing not so good things. Bring blankets and your own snacks if you want to save money. Maybe a couple chairs to get off the wooden benches.
The speedway might not have a lot of other things to do other than watch the races, but you can find a lot of fun in doing that. We like to pick who we think will win when they first start off or even while viewing them from the stands while they're in the pits. They also have a concession stand with nachos and other stadium foods. I would recommend it for parents with kids over the age of 8 unless they're really into racing. :)