Loved Kichijoji, my son moved to Tokyo last year and he has been exploring using the Tokyo Maze book. Kichijoji was one of the areas, we loved it a lot. Lots to see and do, and that park is stunning. Many of the areas we explored had very few obvious tourists, which was lovely.
Son lives near Shinsen station, in those tiny back streets, hard to imagine you are 10 minutes walk from the Shibuya scramble crossing. You just need to wander a little bit away from the big tourist draws, and you can find your peace.