I had watched about a million Dutch cycling videos before I went to the Netherlands, but it's even better than the videos make it out. Cycling in the Netherlands is safe, easy, and fun. I rode around with a four-year-old and an almost-two-year-old in a cargo bike and not for a second felt any stress or fear (and my kids absolutely loved it as well, fresh air and no carseats). I can't go half a mile in Seattle without…
Cycling in Amsterdam is fun in a sort of stressy rollercoastery way. Utrecht is even worse. If you're in the area though, I can highly recommend taking one of the many bike routes, in particular one that leads to the dunes near Amersfoort. From Amsterdam/Utrecht it's a perfect distance for a day trip and really beautiful.
I biked with the kids from Haarlem to Bloemendaal aan Zee. It was the best! Took me a while to figure out Bloemendaal aan Zee and Bloemendaal are different places, so there were some wrong turns, but it was fun all the way.