Karen's place is really good for families with young children. The room was spacious and pretty child-safe. There were plenty of wonderful toys and books which Karen and son generously shared with us. Karen was friendly and helpful with travel and dining tips in the area, and really sweet with our toddler.
Karen's apartment is a couple of flights of stairs from the ground floor (we could leave our stroller on the ground floor). We took approx. 10 mins to walk to the tram stop. Only tram 13 goes to the old town and Zurich main station, but it comes by quite frequently. There is at least one convenience shop and a few restaurants within 5-10mins walk from Karen's place.