.I went down to Mexico a couple months ago and used an offline mapping app called MapsWithMe.

Although I use an iPad mini, I see on their devices supported page that it is available for android phone and tablet models as well:

"maps with me download"

The nice thing about MapsWithMe is that you download an entire country or countries at home over your wifi connection and keep it on your smartphone or tablet's internal storage for offline access. You can use it all day every day anywhere in the world offline without having to have a GPS or cell connection.

While traveling, you can pinch to zoom in on the small roads less traveled. For use in Mexico it also has bancos (banks), mercados (grocery stores), gasolineras (gas stations) and points of interest as you cruise around out in the sticks and one can easily see how far away the next Pemex Mexican gas station or ATM is. On a motorcycle I keep my tablet in the top box and stop to look when I get lost or need to get the lay of the land. But I reckon you could jerry-rig some way to hold a smaller tablet or phablet on your handlebars in a waterproof ziplock or some such. In the truck, I keep it on the seat next to me for checking at a stoplight or when I pull over. A dash mount and cigarette lighter charger would probably make it more useful in a car. It was all I needed.

I find the bigger screen actually easier to use than a GPS since you swipe and tap rather than pushing little buttons to zoom and navigate around the screen. An added plus is that a smartphone or small tablet redraws the screen an order of magnitude faster than a GPS.

Another nice feature of MapsWithMe is that it allows you to download an entire country and then delete it when you get to the next country so you don't fill up your internal storage. You can re-download the same country later as many times as you like. The app is free for the iPad that I use. I imagine the same is true for the android play store. There is a Pro version that adds turn by turn navigation and other useful features I don't need. I bought the paid version just because I find it very useful and like to see developers make a living.