Howdy y'all.
Thought I'd chip in from across the pond re: that new fangled internet google maps on your phone.
You can download a prescribed area of a map before your journey. Do this by tap and holding an area, scroll down on the pin location info > download. You can then zoom in/out to choose the desired area and save the data to your phone. Think the max is 200mb or so which is usually a few hundred square miles. I downloaded most of Sicily and crete this way and navigated fine without data on the way.