Rotterdam definitely not a bad idea as the airport is a comparable size to LCY, so you don’t lose precious time getting in and out.

When I commute to Noordwijk, I generally prefer RTM to AMS for precisely this reason, even though AMS is about 10 km closer.

In fact if the weather is good, you could consider going to Noordwijk, it’s a toned down Dutch version of Brighton, with plenty of mid range independent bars and restaurants.