Getting to Haarlem
Haarlem is easily reachable from the city by public transport in under half an hour.
Trains from Amsterdam Central Station to Haarlem's beautiful station run numerous times an hour departing from track 1 or 2. Some of them make a stop at Amsterdam Sloterdijk station but either journey will take no more than 20 minutes. The last train to and from Haarlem departs around 1:00 am. You can plan your trip using the journey planner on the NS website.
If you find yourself closer to the Elandsgracht area, you might be just as quick taking the bus 80 from the Elandsgracht bus station to Haarlem. The journey takes about 40 minutes. If you exit at Tempeliersstraat stop you will be right at the bottom of the main shopping area and a five minute walk from either the Frans Halsmuseum or Haarlem Stadsschouwburg.