We visited Amsterdam for 3 days as a family of 4 (kids aged 15 and 12). Martijn was very helpful in the run up to our stay. Parking cheaply close by is tricky but Martijn directed us to the Park and Ride (P+R) at Bos en Lommer which worked out at just €1 per day (bargain!)
The property has a steep windy staircase up from street level, but Martijn very kindly carried our heavy suitcases upstairs while we parked the car.
The property itself was clean and well presented - 2 nice double bedrooms, a good sized bathroom with shower and an attractive little lounge/kitchen. Well located next to one of the canals and very walkable to the city centre (Ann Frank museum just a 15 minute walk - make sure you buy tickets online well in advance!!)
We had a great time and would recommend this property as a base for exploring the city.