Everything is big.
The walk or drive from your hotel to the stadium is (probably) big.
The line up to get in in the morning is big.
The line up to get out after the day is done is big.
The walk from the stands to the pits is big.
The walk from the pit entrance to your pit is big.
The walk from the pit to the playing field is big.
The walk from anywhere to anywhere is big.
They sell concessions in the pits.
There are other things going on in other buildings. These will take a walk or a shuttle bus or other form of transportation. Plan on letting your students go to these other buildings somehow. If you normally have a rule about "don't leave the building" you may want to think about how to work around that.
Last year the Fedex Innovation Challenge was a great excuse for half our team to be wandering around the streets of downtown St. Louis.
Visit the Arch. There will be a ton of other teams doing the same thing so it's also a chance to be social!
One potential tip: If your group isn't huge, instead of hotel rooms, considering using HomeAway or AirBNB to rent a house suitable for however many people are travelling. We rented a house big enough to sleep 15 people which was about perfect for our needs, and we had a great time. A parent volunteer took care of cooking meals.