What I do is tether my Ipad to my Iphone (hotspot), bring up DJI GO app so it loads the maps for my current (flying) location. Once I see the map of the area, I "untether" my Ipad from my Iphone and continue with the rest of my preflight checklist...
To the OP - If you can afford it, I'd go with the the Ipad
Mini 4. It has a faster processor and is still produced by Apple which means it'll be supported for a longer period of time. I notice my Ipad Air, which has the same processor as the Ipad
Mini 2, can sometimes lag a little at times, momentary freeze, or draws in a partial "green screen". Never so bad as to be a problem. Just something I noticed. My Ipad
Mini 4 and my Ipad
Air 2 have no such issues.