If you're not renting a car, you basically have 4 options. DL Express bus, not a free service but the only option that doesn't require a safety seat for kids 8 and under, shared shuttle, private shuttle or car service and taxi/Lyft/Uber. The break even on a private option is likely more than 3 people, but with a shared shuttle there could be other stops. Some of the private car services offer a grocery stop, which you might want if no car and will be eating in the room before races. You'll have to price a ride share like Lyft/Uber on your own and figure out if the convenience is worth the price to your location.