Keukenhoff and Kinderjiik routing options

From Amsterdam the Keukenhof (mind the spelling) is best reached by taking the train to Schiphol airport and then change to the Keukenhof Express bus. Their website gives all the information.
The most agreeable way to reach Kinderdijk (mind the spelling) is to take the Waterbus river ferry from Rotterdam. It leaves from the Erasmusbrug, which is a short tram ride from Rotterdam Centraal. Use their website or the public transport planner 9292 for the schedules and connections. The Waterbus continues to Dordrecht: a much overlooked historical city. From there you can take the train back to Amsterdam. (If getting from Rotterdam railway station to the Waterbus landing sounds too complicated, you can also take the train to Dordrecht and there change to the bus to Kinderdijk at the bus station, which is just in front of the railway station.)
I find it a little bit much for one day, but it is possible. From the Keukenhof you can take the same Keukenhof Express bus to Leiden Centraal, to pick up the frequent train to Rotterdam Centraal (or Dordrecht).

I was in Haarlem on Kings Day last year, to avoid being in Amsterdam. Be careful that public transportation to your hotel in Amsterdam is available after your day out touring Keukenhof and Kinderdijk. Last year some bus and tram lines in Amsterdam were not running. You don’t say where your hotel is located.
You will love Keukenhof!

We went to Keukenhof last year. In order to truly appreciate this treasure, I would allot the entire day including travel. Try to go on a weekday if possible. I would also allow an entire day for Kinderdijk and consider Dordredcht together. Zaans Shans has a nice collection of windmills and has tourist-type features.
You have been given good suggestions regarding transportation.
Enjoy your trip!

When you exit the Rotterdam train station, take Tram #7 to the Waterbus, last stop. No, do not combine Keukenhoff and Kinderdijk the same day.

I am not badmouthing public transit, but you are discussing special destinations, not just getting around Amsterdam. You have to add considerable overhead time. Even with a car, Kinderdijk was a problem because I forgot to “check” “Avoid Ferries” on the GPS.

Just to make it harder, are you interested in the Aalsmeer weekday flower auction?!

Thank you for your responses and the information provided. It has been helpful to me.