Don't know how I missed this! The Visitor's Bureau is offering (has been all through October) walking tours of "Haunted Flagstaff. Two days left--tonight and tomorrow night, Halloween. Hopefully, you can still make reservations, although it isn't absolutely necessary to reserve a space.
Tours begin at 5:00 p.m. and 7:00 p.m. from the Flagstaff Visitor Center at the train station downtown. Before you go, you might check out this spooky pdf.
Sounds like a terrific way to spend a Halloween night.
Get more details at the CVB or call 928-774-9541.