Suggestions?

Are you renting a car or sticking to trains? Even if relying on train or buses, you can still reach a number of places to keep yourself occupied for day trips if you just want to base yourself in Rotterdam the entire 5 days. Den Haag is an option, as is Delft. In June, you can take a boat from Rotterdam to Kinderdijk. You could also think about spending a night or two in Belgium and take the InterCity train - Antwerp, Ghent, Bruges.

Depends about your interests, you can base yourself in another place. but you can rent a car and explore the Delta Region south of Rotterdam and even pay a visit to Bruges. Or visit other parts of the Netherlands as distances are short. A lot of places are within an hour reach by train, so possibilities enough for sightseeing.

When my daughter and I first got to Amsterdam, and checked into our B&B, we took a canal cruise tour. I was so amazed at how ingenious the Dutch are. The way they took swamp areas and used windmills to drain them; built up the ground with pilings, then built their homes on those. The Government taxed them on the size of their house lot, so they built narrow houses and built several stories. Then the Government taxed the size of their door, so they built smaller doors and put in the pulleys to lift their furniture into their homes that way. I became amazed at how clever they were to figure out ways around the tax system. Their taxes are still the highest anywhere. But one good thing is - everything you buy, the tax is included in the price. I wish the U.S. would do that, then you know exactly how much you need when at the cash register. The tour was good in many ways as they told of the interesting places to go visit. Rick's guide book was very helpful too. We also found that even though they would say they didn't speak English very well, they ALWAYS knew what we were saying. Very friendly people.