Citywalk is nice but parking is a pain. After paying for parking, you will be directed to one of the parking garages, and depending on how busy it is, may have to park far from the walkway. Then it is still a long trip to clear security in the central hub and then another long walk or ride to Citywalk.
Parking is $17 per car, free if someone in the car has an annual pass. They use to discount parking after 6pm for folks who only wanted Citywalk but I'm not sure if that is still the case.
HTH, Steve.