How late in the Fall will you be making this trip? It gets cold early in the higher elevations. We had our hose freeze in Williams, AZ in early October.
If you get as far west as Flagstaff make sure a visit to Sedona is on your stopover list. The scenery in the area is beautiful.
The Albuquerque Balloon Fiesta takes place October 4-12 and camping will be had to find. If you are near the area during this time, try and go to the Fiesta and see all the balloons lift off. It is one of our favorite stops. Check out the Sandia Casino parking lot if you can't find a campsite.
We've traveled I-10 from Tucson East many times and never felt unsafe.
Have fun.