CR parking is for guests staying at the resort or using the resort features (dining) for a limited time. It is neither large enough nor intended for theme park parking. If folks leave their cars there and go to the MK, guests paying a lot of money to stay there are unable to park their cars.
I agree with the others. Park at the TTC, monorail to CR for breakfast, then walk to MK for the day. When you are done just Monorail or Ferry back to the TTC and get your car.