Itinerary help

I didn't find the Hague that appealing, but it is easy to do as a simple day trip from Amsterdam. You could also include Delft on that same day, although I have also spent two nights in Delft (which I adore).

When is this trip?
The old town of Utrecht is quite small, I think it's a better day trip than a destination. Rotterdam is a vibrant city with many moods- I'd stay there at least three nights. Just my experience and opinions...
Where are you before and after, and is Jet lag an issue, or are you cruising, maybe?
There have been several TR's posted in the last several weeks, including my own. If you review them , I think you'll have a wealth of info to help you plan your trip.
Have a great time!

Our trip hasn't happened yet, but we plan to stay in Rotterdam and day trip to the Hague, so I agree that the distance seems feasible.

Rotterdam, den Haag, Delft, Dordrecht, Leiden and Gouda are all very close to each other, very well linked by train and tram, and there is even a day ticket covering all. Very easy to stay in any and visit the others. Less checking in and out, too.

Gouda is on the train line between Rotterdam and Utrecht, by the way.

Same goes for Haarlem and Amsterdam, and Amsterdam isn't a million miles from Utrecht either. I tend to prefer staying in Haarlem - Amsterdam is too busy for me.

Dutch trains run ever so frequently on clockface schedules, and connections are super easy

I spent 2 nights in Delft, arriving midday. It is small but a wonderful town. Took a day trip to Lieden, which I highly recommend for a full day, plus a great canal boat ride.

Agree with 4 nights in either Rotterdam or the Hague. They are very close to one another. Also, either should be less expensive than adding nights in Amsterdam.

Which one? I prefer The Hague. I suggest you look at your planned day trips and pick the city with the best connections.