Interesting, just read it. However, the article states they used an old fashioned paper road map and not a GPS/navigation :)

[quote]Because of Mr. Kim's background as a technology analyst, observers speculated that the family had used online mapping to find their route.[18] However, Mrs. Kim told state police that they had used a paper road map,[19] an account supported by the Oregon State Police, which reported that the Kims had used an official State of Oregon highway map.[20] Mrs. Kim later recounted that, after they had been stuck for four days and were studying the map for help, both she and Mr. Kim noticed that a box in the corner of the map bore the message: "Not all Roads Advisable, Check Weather Conditions".[21][/quote]