First, internet access will likely disappear after the fall of civilization, so whatever digital content you have on hand will be the sum total of your reading material. Sure, there's always a chance that you might be able to loot another ereader, and there's a chance you might be able to barter an exchange of ebook files, but there's really no way to guarantee either situation will present itself.
That is why I would suggest making multiple backups of your ebook library on SD cards, microSD cards, or whatever removable media works with your preferred ereader. In fact, I would back up an ebook library on both types of cards.
Second, manufacturing will probably also die out as the survivors of the apocalypse struggle to provide basic necessities. At the very least, it seems highly unlikely that any freight shipments would make it out of China, so it would be a good idea to have backup ereaders on hand just in case.
Here is why the multiple backups on multiple card types are a good idea. For all you know, the next ereader you loot might not take the whichever card you were using with the last ereader.
Third, power will also be an issue. Now would be a good time to start planning on alternative power sources, whether wind, solar, water.
Your first thought might be to add a solar panel to an ereader. I wouldn't; a panel the size of your average ereader is not big enough to provide enough of a charge. Also, if the ereader dies your work will be in vain. No, it's better to look for more general solutions to the power issue.
I myself live not too far north of a couple nuclear power plants, so assuming that a minimum of order is maintained and the plants themselves are not destroyed I should still have power - so long as the now-elderly plants continue to function. And if the nuke plants are destroyed, there is an upside. Once I glow in the dark, I won't need a light for my ereader anymore.
But even I have started working on backup plans for a power supply. Wind and water aren't serious possibilities here. I'm looking into solar panels, but there seems to be a run on the limited supply as people stock up in anticipation of the end of the world. That leads me to my plan B.
A generator outputs power when it is rotated. It doesn't matter whether it is pushed by wind, water, or muscle; it just needs to turn. That means that a fixed generator can be run off of dogs, cattle, or even people running in some type of hamster wheel.
The people part looks to be the best option. Chains are readily available, and manacles can easily be manufactured. I fully expect to have an available supply of labor, and even after I factor in the cost of hiring the guards I should still be able to power my ereader and whatever else I need to run.
Yes, this will be brutal on the slave labor, but sacrifices need to be made in order to maintain a bare minimum of civilization. I'm sure they'll understand.
So there you have it, folks. I have accounted for content, hardware to read it on, and power to run the ereader.
Have I missed anything? If you can think of an improvement, please feel free to leave a comment.
P.S. In my next post on surviving the post-apocalyptic world, I will show how two problems like an excess population and a food shortage can have complimentary solutions. Stay tuned.