With all the complaining about Apple Maps I thought I should report my great experience.
I have been traveling between Utah, Arizona, Nevada and California visiting some national parks. In most of these parks and often on the road between them, there was no cell signal. Despite this I was able to use my iPhone 5 maps to give me turn-by-turn direction from door-to-door despite having no signal.
I first had to have the map prepare my itinerary with a data signal. Once it was done, I would turn off the "data roaming" (as I have a Canadian supplier and don't want to run crazy charges). Then I would get clear directions all the way with no data and often with no cell signal. It was a great help and made the trip relax.
The key is to have a data connection when you start the trip. Just thought I'd share this.