Honestly, I think the internet/data is the least affected during electricity issues. These systems have massive government supported backup systems. I think you are more likely to run out of battery/electricity. Then, if the internet actually fails for a long time there will be some moving USB sticks of stuff like wikipedia and maps. Like in Cuba. These days you can transport petabytes of MicroSD per hour with a bicycle, if you want. Assuming it is that bad, I would more likely buy a survival guide, some do it yourself books and paper maps.
Conversely, how likely is it that you have such internet problems while still having reliable electricity? Intuitively I'd say it's unlikely, but I'd be curious about others' opinion.
I don't see myself browsing through local files on a computer while internet is down, I expect to resort to books and daylight instead.
