osmand
If you have a smartphone or tablet, using Android, the free or low cost Osmand lets you download regional maps and store them on the device. Then you just need a GPS signal.

It's not the best solution for navigating while riding along (since the phones or tablets displays aren't good in bright sunlight, etc.) I rode with a rider that had the osmand voice prompts with the phone in his back pocket. Never tried it myself that way.

But osmand launches quickly and shows you where you are, and what's nearby. It's way easier to browse omsand maps by panning and zooming than it is with my old Garmin 705. And osmand shows hill and mountains with shading and countour lines. With Garmin's reputation, the newer models are probably annoying to use as a map browser, too.

Osmand can import routes and display them on the map. It can be a little complicated, so get used to the method of importing before your trip. I've only tried route imports via a USB cable. Maps and map updates are normally downloaded via wifi.

It can calculate a route to a destination -- but it's not as sophisticated as a google maps route, you may need to route to a few intermediate points to force it to follow your preferred route when riding a bike.

I reviewed osmand in this thread.