Yes, if you rely on google maps or any app, make sure you download maps. Otherwise like the young couple we met on saturday on exmoor who hadn't you'll have to ask the old gits, us, if you can photo their os map!
An ipad with mifi will work but unfortunately only the ones with a sim card slot have a gps chip. I leave the ipad sim slot empty and tether to my iphone hotspot or mifi. It is a mean trick of Apple to leave the gps chip out of the basic ipads.