As to the final city: Logic suggests that it'll be a city on or near the east coast and probably not Miami or New York (as the last two east coast cities that saw a final mat.) That would leave, at a minimum Atlanta, Boston, Washington DC, and possibly others.
As I'm sure Georgia Peach will attest, Atlanta does have a few locations to hide the final mat that wouldn't be obvious (the state park at Stone Mountain east of downtown is one, a state park at Lake Lanier is a second, and somewhere along the federally managed park areas of the Chattahoochee River to the north and west of the city center as a third. There's also the possibility of having teams use the subway system out of the airport to an area along the subway lines. (There's also the Olympic connection and we all know how much Bertram loves using Olympic cities for TAR, and Centennial Olympic Park downtown Atlanta is on the subway line.) Now that Delta is officially the world's largest airline and Hartsfield-Jackson is usually listed as the world's busiest airport, Atlanta sticks out to me as a TAR finish mat like a sore thumb.
