From I-44 in Webster Groves, take Elm Avenue south to East Glendale Rd. Drive east all the way to Edgar Road and turn south one block to Oak Tree Drive. Turn right on Oak Tree Drive and the parking lot is on the right.
From Watson Road in Webster Groves, drive north on Edgar Road to Oak Tree Drive. Turn left on Oak Tree Drive and the parking lot is on the right.
You will find a Mapquest map here.