Potential itinerary for late March/early April

https://community.ricksteves.com/travel-forum/trip-reports/the-netherlands-belgium-april-2024-brought-the-rain-pants-needed-the-rain-pants

You'll be in the Low Countries during tulip season so grab lodging asap. My attached Trip Report may be relevant to your specific areas. We had a great time spring, 2024.

Enjoy!

Have you been to Paris before? From Paris, if interested, you could look at going to Versialles or Chartres for a day, or Giverny.
From Bruges I highly recommend Ghent for a day. We went to St. Baarts to see the gorgeous altar piece and then followed the RS guide of the city center. If you want to see the altar piece you must purchase tickets in advance.
From Delft, we went to The Hague, we tasted Genever at a historic shop/production, walked through the city and along a park to the Peace Palace. If you don't/can't get into the palace, there is a small, but very interesting museum.

Jules, I have been to Paris but it's been about 20 years. My husband has also not been in many years. Thanks for your suggestions!

Just a couple of notes. Giverny won't open until April 1 this year. But Versailles is certainly an option for a day trip from Paris. Keep in mind that the 23rd is your arrival day, so you may be jet lagged and tired. And the 28th is a travel day. So you only have 4 full days in Paris.
With both Mar 28 and 30 being travel days, I don't see any time for a day trip from Bruges, if you want to explore Bruges.
With tulip season starting not long before you arrive, now wouldn't be too soon to book your Amsterdam reservations. If you want to see the Anne Frank house, tickets go on sale on Tuesdays for visits 6 weeks later. Once fhey are gone, they're gone.

I've been to your locations this time of year. The year I went I was on a RS tour of Belgium and Holland and we had snow on our day transiting from Delft to Keukenhof. I recommend a good waterproof rain jacket with hood that you can layer over a puffy vest or jacket. I also recommend lightweight glove liners.

When I was in Paris at the end of March many locals on the Metro were still wearing heavy wool winter coats. I managed with my puffy vest but I am pretty cold tolerant. OTOH, I was in Paris the beginning of Oct in 2024 and had to go buy a LS shirt because I'd taken mine out at the last minute and just had short sleeve tops. What was I thinking??

I also agree that if you are in Bruges for 2 nights that just gives you 1 full day and there is plenty in Bruges to keep you busy without doing a day trip.

You'll just be in Delft the one night so not time to do a side visit to Den Haag. I'd just stay in Delft and enjoy it, then move to Amsterdam.

I'm glad you are giving your little one the travel experience before they are born, lol! Congrats!

I wasn't sure how days/nights were being counted. If you only have one day in Bruges and Delft, you don't have time for anything else. I did verify that Giverny is closed until 4/1, anyone know why? Its my understanding that it is supposed to be open year round. That said, I don't think March would be the best time to go, though fewer people would make for lovely water garden photos.

RH, I don't think the gardens were ever open year-round. March to November, meaning lately April 1 through Oct. 31. There wouldn't be much to see in the winter.