Tip: there are just a few steps in to the apartment (well lit entrance, safe), and then it's all on one floor with a walk-in shower. Friendly for all ages :-)
If you want to be in Kralingen (a pretty, residential part of Rotterdam that's close to the centre), this is a wonderful spot for a longer stay. Lovely owners, clean and up-to-date space with everything you need to feel at home, and right across the road from a lake that's great for walking, coffees, and people/dog/bike/horse watching.