We stayed three nights in the Room Upstairs and Marta is a very friendly and nice host. We got a map of Amsterdam and even a guide in German. With the bus you can reach the city centre in about 25 minutes (there goes a bus every 10 minutes, the whole day). But you should know that the place is not in the centre of Amsterdam.
There is one important thing you should be aware of. There are pets in the house and if you are allergic then this is not the place for you. Besides there is no TV in the room as it`s said in the description you have to pay extra for that.
All in all the room is very nice and you can sit outside on your "own" roof terrace.