In the short term, I think a mobile phone with an offline copy would probably be fine. You can buy something with a large amount of storage (you need 100 gig or

In the short term, I think a mobile phone with an offline copy would probably be fine. You can buy something with a large amount of storage (you need 100 gig or so for offline wiki with images), is fully waterproof, more portable and can be EMP shielded in a metal box easily. Charging is also easy with a small panel and a power bank. You can also store offline open street map (OSMand) and you have GPS built in, though in the apocalypse that would stop working eventually too. I think they would actually keep transmitting (it'd make sense from a military perspective) but eventually they'd lose station-keeping ability if they don't get orbital corrections from a ground station. The main problem you'll have is that mobile apps and OSs tend to do weird things if they're offline for an appreciable length of time. Lots of things randomly stop working because caches become invalidated. Anything that requires a login or an app that tries to update (and fails to connect) is liable to break eventually.