Viggo Mortensen for The Road?

The Road, Cormac McCarthy's superb novel, is certain to be one of the bigger PA movies when it starts it's transfer to the screen next year. MTV is reporting today that Viggo Mortensen (Aragorn in Lord of the Rings) is in line to play the Father character. A great casting or a bad idea?

http://moviesblog.mtv.com/2007/09/11/viggo-mortensen
-ready-to-hit-the-road/