My college-aged daughters and I spent a week visiting family in Den Haag mid-March. We made 2 day trips to Amsterdam, which is about a 45 minute train ride. We also did an overnight in Brussels (my brother drove us).
Here are some highlights:
Amsterdam:
-The Rijksmuseum. The national museum of the Netherlands, which includes, among other treasures, the MASSIVE "Night Watch" by Rembrandt. https://www.rijksmuseum.nl/en
-Anne Frank House. As mentioned in another post, booking up to 60 days in advance is a must. Please include this in your itinerary. These days, we need to see this more than ever. Remarkably, everyone visiting was on their best behavior. It will stay with you.
https://www.annefrank.org/en/
-Those Dam Boat Guys canal tours. Funny and informative, with smaller boats. Our tour guide, Axel, was an Amsterdam native, and really knew his stuff. You can bring food, wine, smokes, "as long as you're not a d**k about it"!
https://www.thosedamboatguys.com
The Hague:
-We went to the Gemeentemuseum, and local shops and restaurants. Coffee is a big deal! We could see the North Sea from our hotel, but ran out of time before we could hit the beach. The Mauritshuis museum has Vermeer's "The Girl With A Pearl Earring". Lots to do here!
https://denhaag.com/en/
Brussels:
-We grew our brains in the interactive visitor's center (The Parlamentarium) of the European Parliament. It's free and open 7 days a week! Brussels city center is lovely, the buildings are very French (white marble, blue tiled roofs, gilding). It's about a 3 hour drive from Den Haag.
Rotterdam:
-We made a quick stop on the way back to DenHaag. It's a very modern city, since it was rebuilt completely after World War II. It's very hip and cool! We did some shopping at the department store De Bijenkorf (the Beehive), also in The Hague and Amsterdam. It reminded me of the full-service department stores we used to have in the US. There's a cafeteria-style restaurant on the top floor too.
We had a great time! If you go in March, dress for the weather. It pretty much rained every day, and the wind is like I've never felt before. As always, walk, or take the trams and trains. I felt very safe there.