I hadn't heard about mapwithme. It's also based on Open Street Maps. It might have some good features for non-automobile use, perhaps more points of interest and ways of tracking your location.

Osmand on google play is free with up to 10 map downloads. I think the first one or two are the base maps, large coverage maps (worldwide?) with just major highways and cities. The separately downloadable regional maps are state maps here in the midwest, so it's easy to get your state and bordering states for free.

The "osmand+" $7 one-time pay version to get more regions is mostly to help support more development. (Both the osmand software and the Open Street Maps themselves are open source, which allows free usage and modification or adaptations for new uses.)

Osmand does a pretty good job of car navigation, including optional voice prompts for turns and zooming in when the car's speed slows down. It can keep the map oriented to North, or turn it in the direction of travel. If it picks a route I don't like, I add a waypoint in the middle to get it to go the way I want.

Last fall, one rider on the group ride had osmand (or something that sounded exactly like it,) running on his phone in his jersey pocket, calling out turns! It actually worked pretty good! He probably downloaded the route from ridewithgps.com, but I don't know how he linked that route file to the mapping software. But this was a 3 hour ride, not a multiple day tour.

For exploring, the map can be dragged and zoomed with the usual android finger motions.