Exit onto the Henry Hudson Parkway, and then onto Riverside Drive (south).
From Riverside Drive (Southbound)
Turn left onto 165th Street (the first left south of the bridge). Proceed three blocks and turn left onto St. Nicholas Ave., then turn left into the Audubon Center parking lot.
From upstate New York and New Jersey
After crossing the George Washington Bridge, follow signs to the Henry Hudson Parkway (aka the West Side Highway), and then to Riverside Drive. See directions from Riverside Dr. above