Yes, the GPS can be very handy. Take a look at Winmapper by ioan, to download the maps to a PC, then transfer to an SD card. Or, personally, I just set the map repository in maemo-mapper to put them on the internal SD card, grabbed a big map of the world, and then zoomed in from there to the places I typically need and grabbed more detail over my home wifi. Either works well, just personal preference. Just be sure to get a zoom level that gives you major roads if you're going cross country.