Perfect location, 1.5km to charles bridge and I walked there twice, morning and night, both times feel very safe. If you are not like me, take tram at downstairs to both old town and castle in 10-15 minutes.
Josef is super host, very good communication. He provids excellent guide book with all details.
We are group of 4 adults 4 kids, there are plenty of room for us. I highly recommend this place.