I just spent a week in Aalsmeer, which is a 40 minute bike ride from Amsterdam (or a 40 minute drive). Since it doesn’t have a train station it was inconvenient to get anywhere without a car. That said, if you are near a train station, pretty much all the major cities are within 30ish minutes of one another.
That said, I think it’s more a function of the Netherlands being a small, flat and dense country than having great public transit. You could probably bike between most major cities in less than 90 minutes.
