[creaturecat]

Haarlem - beautiful city square, couple of fantastic bridges.
Amsterdam is where the museums and cosmopolitan lifestyle are. Van Gogh museum, Rijksmuseum to name a couple. A beautiful city to walk about - VondelPark, a great place for a picnic.
What time of year? Florence and Rome are absolutely packed in the summer. Hotter than hell as well. Shoulder season is the absolute best time of year. Less expensive, more locals, shorter lineups.
I would do London, Paris, Amsterdam, Haarlem for the family.
Fly into London, train to Paris, RyanAir to Amsterdam.
Expensive and timely to travel to/from the airports (RyanAir type airports) the exception being Amsterdam.
Fantastic train service to areas of interest outside of the the major Cities. Nice way to meet locals and fellow travellers.
A car can be a total headache. Expensive gas, tolls, no where to park, cars not allowed in some areas.