>smartphone or a tablet, anything that can be used to access/store modern data formats like .doc, .txt or .jpg
Android can do all these things but I have no idea about other OS' capabilities. Apple doesn't sound like a good idea for that kind of things.
Absolutely no experience with the Windows or other line of these.
>anything that can be used for data storage:
usb sticks
SD, micro-sd and similar memory cards
external HDDs
internal 3.5" HDDs for when you get to run a stable desktop. These things are bulky though so they should be limited to high capacity ones and even then, external HDDs are easily acquirable. Maybe just get a spare one that runs a clean OS so it could be used to access desktops if their main OS drive is damaged?
Also, carrying a DVD-ROM and a bunch of discs wouldn't be wise because It takes time to store data on the discs and they can't be reliably accessed. Also, discs degrade and I'm not even sure you can burn them from an android device.
>external batteries
Those fucks that provide charge until depleted. Uhhh, portable chargers and the stuff.
Would be better to bring some spare li-ion batteries instead but then again, modern touch screen PDAs are sometimes made with built-in batteries.
>one of those hand crank or some kind of dynamo chargers
Don't know much about these, just saw them mentioned a few times on the internet.
Basically something that is small enough and able to supply the external batteries with charge.
You can hook up mostly anything USB to an Android tablet via a cheap OTG cable. Just get one of those, a USB Hub and hook it up to an external battery so it supplies these things with power if the device doesn't produce enough energy to power all the connected shit. You can basically connect a laptop mouse and a small keyboard to it. I don't think simple USB sticks need power though so if you don't plan to carry other peripherals the USB Hub might not be needed.
Android doesn't support all modern formats natively though so getting some apps and backing them up on some storage might be wise, maybe there is a torrent up but I haven't looked. IIRC for example .doc or .ogg files aren't supported by most stock builds.
Another thing is protecting these things though. Touchscreen devices aren't exactly built for harsh conditions. It would be wise to look for some protective screens and rubber cases. Maybe there are some heavy duty models or protective cases on the market?
Also not all devices respond to gloves or other hand covers so bringing a stylus would be ideal.
Oh shit also earbud headphones are important. You might want to bring some over-the-ear headhpones too but something smaller. Over-the-ear headphones that supress background noise for example.
That's all I could think of. This is just my personal guess because I don't have any experience with these things and they aren't exactly tested for reliability. Maybe ask some chum from /out/ or some other innawoods kiddies from /k/?