I'm in the MotionX camp, I have MotionX GPS.:| $1.99 to buy, then $5.99 so you can download and use custom map sources.
I'm like you, I have a spare iPhone 5 left over from an upgrade.:| It doesn't have a plan associated with it, so it's only good for 911 calls (I think).:| However, Wi-Fi, GPS, and Bluetooth still work.:| There is a bit of a learning curve with MotionX.:| You want to set up your maps and download the needed segments while you are on your home wi-fi, and that can take a LONG time.:| If you want to download a large area, download it in segments totaling less than 100,000 tiles, then grab the next section.:| Don't worry about overlap, it will only download the tiles for that section if you haven't yet downloaded them.:| You can play with upper and lower zoom levels to tailor how close or far back you want to look, the the closer you get (more detailed), the more tiles you will have to download. :|
There is one niggle I'm still trying to figure out, and I'll admit that I haven't played with it too much in non-cell mode.:| When using the phone in non-cell service mode, it seems that some movement is needed before it starts tracking on the map, then it's fine.:| Before then, it just shows the "No Data" tiles.:| It's a little frustrating, because I want to look at the downloaded maps for an area 250 miles away, but it's being goofy on what it shows.:| I need to drive a little to see if that kicks it into gear.:| However, I used it on my regular phone (with cell service) last year to do the COBDR, and it did fine.
Another thing to point out is that MotionX GPS doesn't have turn-by-turn voice instructions.:| I heard another one of their products does have that feature, but I use Waze on my main phone for that, because I only need it for street use.
I'm working hard to have this work out.
Caveat::| I'm not riding in any critical areas (yet), and have my main phone, ancient GPS, and paper map as backups.
To download satellite imagery and USGS tops maps
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