Taxi - Taxi service from the airport is approximately $40 each way.
Chesterfield Tax and Car Services offer an inexpensive alternative to taxis for attendees traveling to and from the airport. Visit their website to book your car service from the airport to the hotel and vice versa: http://www.chesterfieldtaxi.com/. The Chase Park concierge will also book through their service when leaving the hotel--just ask.
Metrolink - Take the Metrolink train from the airport to the Central West End station. From the station, it is a 2 block walk to the Chase Park Plaza, or take the #10 bus south from the Central West End station and exit directly in front of the Chase Park Plaza. The Metrolink is $4 each way.