In reverse order. . .
GPS is definitely worth it if you travel. I consider a GPS device "essential equipment" for my vehicle. It eliminates a lot of thinking on what should be on/off. Your only decision will be which Global Range to set (on the keyboard). You'll have to experiment to see which is best, because you can "under scan" (miss too much) or "over scan" (miss too much because you are trying to receive stuff too far away).
Statewide systems are a subset of the nationwide when it comes to scanning the full database.
The "best" way is to use a GPS device. The next best way is to change the zip code when you enter a new county/area (hopefully not while driving).
If it was me, I'd create one big ol Favorites List for when you travel. I would set each county as a system within that big Favorites List (probably multiple systems if trunked systems are involved). Then I'd set the Favorites List to Location Control On. Then using either the GPS device or entering a new zip code (kinda the poor man's GPS), the scanner will turn on/off those things appropriate to your location. The only fussing involved would be entering a new zip code. I'd give this Favorites List a Favorites List Quick Key of 1.
Then, back for use at home, I'd create a second Favorites List for my home area, being sure the change the zip code if no GPS is involved. This Favorites List I'd assign to Favorites List Quick Key 2.
That way when you are at home, turn off FLQK1 and turn on FLQK2. If you do get a GPS device, you may not even have to do this as the GPS device more or less does this for you.
Bear in mind that when using a GPS device, the scanner will remember the last location data reported to it by the GPS device. So if you return home, disconnect the GPS device and take the scanner inside, the scanner will know you are at home.
Last thought, when I did use a portable scanner on a trip, I found I really needed an external amplified speaker to overcome road noise. An external mag mount antenna was helpful too.
