I have lived in Arizona for 12 years now, and in October...the ONLY place I am going to suggest you photographing in along Oak Creek in SEDONA. It is just outside of Flagstaff, you can go there or your way too or from Flag. Do you shoot color or black and white? Of course, its really good for color right now because all the leaves are changing colors.
I am planning a weekend trip up to Sedona one weekend in October. Let me know what weekend you will be there and we could possibly meet up and I will show you a few beautiful places.
I do not suggest photographing around Phoenix this time of the year. No wildflowers, very hot, and dry. You will spend more time hunting for photographs, then you will PHOTOGRAPHING. I only suggest going to Sedona, Oak Creek.