I usually do not depend solely on the GPS as it can be WRONG. I usually supplement it with a paper map.
Yesterday, while coming down from Tulsa, to the Menolia or Canton, TX area, the map was not on the seat where it normally rides and I took the direction from my GPS...know as "EB" or "BB". we wound up going down some really narrow and tree lined county roads in East Texas. We were expecting to see the locals sitting on the porch playing Dueling Banjos
Streets and Trips with the GPS and a netbook work much better that the GPS since it has construction updates.