I'm not sure how much everyone uses those in-car GPS units, but I thought I would pass on my experience with them and something that has been happening around my parents house lately with those GPS's.
I once went to Panama City Beach with one and it took us in a large circle (about five miles). The second time around we realized what was happening and went straight and broke off of it. My second experience happened when I drove to Colorado to go snowboarding. The rental shop was in the middle of a frozen lake according to the GPS. Good thing I have a brain and didn't follow it (how cool would a shop on a frozen lake be though?).
Here lately, two frozen chicken trucks have used their GPS's to take the fastest route around here, which involves going through Albert Pike (a very primitive and wild area). Two trucks have fallen over and dumped frozen chickens while trying to drive the mountain dirt roads. (Which could make for some awesome geocaches while it is cold.)
So the moral of the story is to only trust your GPS so much. I always have a good visual of the route on map before I leave. Pesky GPS's are so demanding. "Turn here now or else... Take one left and eight rights... blah blah blah"
Very demanding...in some cases (I SAW IT ON TV!!!)
they demand the diamond jewelry that you just bought...
During the summer of 2008 the Mz and I were doing the Arkansas State Park ParkCache series. My Streets & Trips with GPS took us through the Albert Pike Recreation area and while we did wind up at our destination the ride was different than I expected. I agree fully about not trusting a GPS totally.
BTW, the scenery was very nice.