My husband and I and another couple are going to travel Route 66 in Az. Before we do we are going to Tombstone on Saturday then Old Tucson Studios on Sunday . We were going to drive on to Holbrook that evening from there but my cousin said the road from Phoenix to Flagstaff is very dangerous to drive at night. We're older couples and don't really see well night driving. Would you advice us to leave the next day? We are coming around the first of October, not sure what time it gets dark there. Thank you for any advice you can give me.