Biggest advice is definitely don't drive if you don't have to. Hop on one of the shuttles so you're not stressing the gridlock traffic on the way out each day. Looks like
shuttles are $79 - $139 this year depending on the pick up location, for the full 3 day weekend.
Food varies, but it's a sporting event in the US, so you already know it's not looking like Costco hot dog prices
If you're avoiding alcoholic drinks, stick to one meal and some kind of snack/treat while you're at the track, you can probably swing it for $40 - $50 per person per day. Breakfast & dinner at home/hotel/somewhere in town is always the move
I'd avoid buying merch at the race, it's overpriced shirts/hats/etc, unless there's something you really need. You can take a look at the
online shop and see what prices were like, and scoop some deals