I took photos from behind the reserved seats on Oike Dori near Shiyakusho-mae Station (with a zoom lens), then I moved to the corner of Oike and Kawaramachi. I was pretty happy with a lot of my shots. You can see some of them here http://en.japantravel.com/photos/gion-matsuri-procession
I went to Gion Matsuri some years ago. This year's main event is practiced on 17th July.
Next site is Japanese, but it's map is parade route. The crossing of Hankyu Kawaramachi station is easy position at 9:40AM.