Netherlands Itinerary, Car Rental and Accommodations

We've been to Amsterdam a few times, and our regular B&B was subdivided into condos. We stayed out at the airport at HotelSchiphol.nl and found it to be an incredible property at bargain prices (for Amsterdam). The rooms are the nicest and by far the largest we've ever experienced in Europe. They drove us over to the airport where we caught the train downtown to the Central Station in 15 minutes or less--quick and easy.
This is the Van derValk chain of business hotels. See Valk.nl/en to see if they have any hotels in the towns you're wanting to visit. You won't be disappointed.

A few suggestions.
Why not combine the daytrip to Alkmaar with Hoorn? A beautiful and pleasant former port city. Or with the Zuiderzeemuseum in Enkhuizen, not too far away. The stretch between Alkmaar and Hoorn is real windmill country, such as the threesome in Schermerhorn but there are many more in their natural habitat. Best done by car.
Volendam and Marken are very touristy. Better combine Edam with Monnickendam, just a few kilometers away. This is another day for which a car could be useful to explore the countryside around.

There are many nice towns an hour or less by train from Amsterdam. I think Arnhem and the Hague are not that close. I did go to Delft for the day, though, so the Hague must be doable. You didn't mention Leiden, Utrecht, or Amersfoort.

Driving a car back to Amsterdam each day is an American conceit that would be like hitting yourself in the head with a hammer. But local transportation (like Rotterdam to Kinderdijk, or Flower Auction to Keukenhof) is too tedious to add on to a train day-trip. We drove from Cologne to Amsterdam in two weeks, but I suggest you use the train.

so the Hague must be doable
Actually you'll pass The Hague en route to Delft, which makes the train journey a little bit over half an hour from Haarlem.
local transportation (like Rotterdam to Kinderdijk, or Flower Auction to Keukenhof) is too tedious
There is an half-hourly »Waterbus« ferry from the Erasmusbrug to Kinderdijk. In season a direct service is added. Kinderdijk can also easily be reached by an hourly direct bus from Dordrecht railway station.
But to get from the Flower Auction in Aalsmeer to the Keukenhof in Lisse looks indeed almost impossible. The easiest connection presented by the excellent public transport planner http://9292.nl/en# involves three changes.

Thanks Tom. When we were at Kinderdijk, by car, we saw some forlorn tourists waiting interminably for the city bus. And having made the drive (I suppose less skillfully than a bus driver!) I thought it was rather far from Rotterdam. My point was that when you are already walking to and from the home rail station, waiting for a train, and learning where (for example) the local bus stop even is, you really don't have time for another 45 minutes or more, each way, to a secondary location. My opinon ...

I hope it was clear that I used the Amsterdam commuter trains extensively. I'm in favor of public transportation for this itinerary.

One could argue that Amersfoort's old town is quite a hike from the train station. But it's kind of a nice walk, and one route passes some interesting history, like THE "town boulder", and a small De Stijl office building.

In Leiden, I made the mistake of depending on an alleged free, inter-museum shuttle bus that never appeared. So I hoofed it, walking miles in the day. But it was worth it.

Never venture on unknown terrain without a schedule and a map...

Thanks to all for some great info. Need to digest, do some more research based on recommendations and will probably have more questions.

You're welcome. Make it a new thread.