We were a large family of 6 adults and 3 babies under the age of 2. Iris' home was the perfect size and quite large for Japanese standards. The bedding was perfect for us all to stay comfortable. The layout of the house (3 levels) meant we all had enough space to have our separate rooms.
The location is 10 min walk to JR Ikebukuro station. There is a supermarket within 5 minutes so everything you need. Highly recommended Iris' property for large groups traveling to Tokyo