Ruud's apartment is very centrally located in the heart of Amsterdam's Museumplein, being ~7 minutes from the Rijksmuseum and ~9 from the van Gogh Museum. The apartment is located on the top floor of an Amsterdam townhouse; the stairs are steep and narrow, so try to pack light! Once at the top, you enter into a hall-like anteroom, from which there is access to the toilet/shower combo, washer, and fridge. The main room consists of a small but well-equipped kitchen area, a table with two chairs, and a very comfortable fold-out sofa-bed. There is also a lovely terrace with a table and some chairs, which would be perfect for a warm summer's evening. While the room is pretty small, it is perfectly adequate for two people to stay comfortably, especially when the bed is folded up. In summer the apartment may warm up during the day, but there is an air-conditioner--a luxury!--available. Ruud left travel guides for us to use, and these were very helpful.
The area surrounding the apartment has several chic wine bars and cafes (with heated outdoor seating!) that were filled in the evenings with a diverse, hip local crowd. There is also a supermarket near the museums that is easily within walking distance. Several tram stops are also located in the immediate area, which will take you anywhere in Amsterdam.
There was some miscommunication regarding our arrival, and so the apartment was not available until later than anticipated, but this definitely seems to have been a one-off occurrence--Ruud was very apologetic and more than made it up to us. Ruud was a very attentive and welcoming host, and checked in with us to make sure that everything was going well. I would definitely stay here again, as it comfortable, clean, and convenient.