I want to see some tulip fields up close and personal and to have the opportunity to stop, take pictures, and walk about. So, we have decided to hire a car and driver, rather than rent a car or bicycles, for about a half day (could expand to full day if suggestions warrant).

I figure we could go to the flower fields between Amsterdam and Lisse, but have no idea what else to visit during the 4 hours. It seems rather a waste of time and money to have the driver sit around while we visit Keukenhof Gardens, especially since we have no idea how long we would spend there -- would it be a good idea, or even feasible, to have the car drop us off at Keukenhof at the end of our tour and then we can make our own way back to Amsterdam from there?

Other possibilities I can think of (although not sure whether desirable via a car tour):

The North Sea shore?
Leiden?
Delft - but we are planning a separate day to visit Delft and Den Haag on our own.

Any other suggestions for places to see/visit in and around Amsterdam/Lisse and beyond would be greatly appreciated.