There are 3 ways to commute to reach this beautiful site
By car: You can get to the free car parking lots (in Alblasserwaard) specially assigned for the cars visiting the Kinderdijk. They are a bit away from the actual site, to avoid traffic jams as the roads are very narrow. These parking lots offer free shuttles direct to the Kinderdijk and are seasonal, so you might want to check them before hand on their official website. If you are lucky, you might find a good spot to park your car on the streets. We had parked at the free lot and taken the shuttle, as we had less time in hand. So, if you too are looking for a quick visit then choose this option.
By Waterbus: You can also plan your visit to Kinderdijk via water transport from Rotterdam. There are quite a few tourist cruises and boats that take you to the Heritage site, it includes hop-on, hop-off.
By Bus: You can also stick to the public buses which runs from Rotterdam and Dordrecht.