I have a Garmin eTrex C, which I plug into my laptop sitting on passenger seat or passenger lap (the then newly designated co-pilot).

This way, I can preplan and layout my route at home from say the airport to hotel to whatever....after that, it's keep the "arrow" on the line and no problem.

Honestly, it makes travel/driving so much easier, especially areas you're unfamiliar with and of course overseas.

The fact that many will also point out gas stations, food, rest areas and more is another bonus.