After much looking the only map I could find of Kiffissia was this road map in Greek pictured below.
The yellow road on the right hand side is Kiffissia Ave. running up from Athens and a major Road which starts in Athens Center. Taking it to its conclusion will bring you to Marathon.
Then I found a map in English of Kiffissia & Poltia which is rather big so it wont fit on a page this size so I made a bigger page for it and then changed it to a smaller one but at least its in English, click here to see it.
Kiffissia is a northern suburb on the slopes of Mt. Pendeli and in past years was rather exclusive. It still is but less so. Here you will find large villas as well as modern apartment blocks, expensive boutiques, bars and cafes. It gets crowded and traffic backs up on weekends.
It is a bit cooler here in the summer but very crowded and Kiffissia traffic is congested on the main roads especially on weekends when people go to dine in their favorite restaurants.
Kiffissia is the northern terminus of the older electric train metro line. A Kiffissia is a kind of vine too.