[link|http://www.garmin.com/products/iQue3600/|iQue 3600 link]. It uses Palm OS and is portable being just a bit thicker than other PDAs. It has the standard Palm applications. The particular unit has both advantages and disadvantages relative to a vanilla car GPS system. For one thing you need to buy an "auto kit" to supply steady power and provide a more decent speaker for the Navigator's voice. The built-in battery would last only a couple hours if the screen remains lit. Also, the built-in fold out antenna needs to be on the dashboard to pick up the satellites. I plug in a separate antenna so that the unit can be placed in a darker interior of the car. On the other hand, I have a larger higher resolution screen and I could take the unit hiking. But, these are buying decision factors.

I got it because, having purchased a motor home, I expected to find myself in places I had never been to before on a regular basis. There is nothing like having local information at hand, especially in more urban areas.

For the most part it has it has performed well for my needs. My first real use of it was last September in the LA area when my wife and I flew out there to visit the factory where out motor home was to be built in Montclair. We also got a chance to meet up with Ben Tilly at a restaurant in Santa Monica and meet Andrew Grygus at his house in La Crescenta. The unit did fine navigating the Freeways, one-way streets, etc. I did screw-up Andrew's address and had to do some head scratching for a while. Heck, I used the unit on the airplane to see where we were including altitude during the flight. But, that's not navigation.

There was serious use of the unit after we picked up our motor home and slowly headed East. Need groceries? Look for a supermarket. Need a laundromat? Search for the nearest one. Etc. Need to get off the Interstate which has become a parking lot and try to make headway on secondary roads? Well, it will continue to navigate you to your destination. As the voice (that I call Destiny) says - "Re-calculating!".

Problems? You bet! They mostly have to do with missing, obsolescent, or bad data. Looking for a Costco store we were directed to one that was 15 miles away when there was a new near-by store. Many campgrounds are not in the data base and alternate information sources are required. We had been directed to stores that had moved or been closed down. We have seen local details e.g. streets be off a few hundred feet! In New Brunswick, Canada being navigated to a campground we found ourselves in rush hour traffic in Moncton, NB and eventually in a neighborhood with family homes and small apartment buildings! Again, using alternate information, we did find the campground many miles away. Turns out we had been navigated to where the owner of the campground lived! Again in New Brunswick, on the map display, we found ourselves moving in open fields with the Trans-Canadian 2 some half a mile away. The new road had been built some distance away from the old one. On the recent trip to Michigan we wanted to go to [link|http://travel.michigan.org/detail.asp?m=4;5&p=G10169|Van Buren State Park] on Lake Michigan. When we got close to the park we found ourselves at a concrete barricade. WTF? Well, if you followed the link and looked at the picture, you get a clue. Those white buildings are a nuclear plant. The South entrance to the park is no longer in use. It's GIGO, of course. So, you have to take directions with a grain of salt and use your head at all times. Data updates for a fee, in my case $75, are available every year or so.

How much area is covered depends on how much storage you have. In my case, I have a 1 GB SD module which can cover close to half the US. The data available is broken up in variable sized geographical "tiles" (my name for them). You get to select the tiles you want be included in your set of data. As you might imagine, a part of Manhattan may have as much data as half of Wyoming. For longer trips, I re-build what goes on the SD module. Some GPS units have hard drives or DVD readers and can contain everything. YMMV.

For cross-country, I would make sure I had all the data and an overall plan and then use daily target destinations. I would preview the selected path as well.

to return you to the interchange you've just exited. You do have a map to look at to make reasonable choices. If the destination is far away it does take a while for it re-calculate a route.

The maps you have are not likely to show streets, county roads, etc., that are available on a GPS system. You would need a book of detailed maps all along your path to match a GPS system.