Agreed, OP didn't ask "what should I do in nepal?" - I'm sure he also has "see nepal" pencilled in. Few answers to this question have been any help at all.
My recommendation: download a bunch of documentation (I recommend HTML format) and take it with you. I'm building my own offline documentation repository right now, and it's kind of fiddly but not difficult. Here's the process:
* create a new directory for your compendium
* for each item on your list, google it, go to the official site, find the 'download documentation' option, and download the docs - they're mostly small, only a couple of megs, and they're rarely difficult to find. In some cases there might not be downloadable documentation. In this case, I recommend wget --mirror
* extract the docs and build a master index file in the root with links to each set of documentation. My index sits in a small frame at the top of the browser window so that you can switch to a certain docset easily.
* When done, To save (lots of) space, use mksquashfs to create a compressed volume which you can mount and read offline.
You'll find the searching functionality of offline documentation limited, but i find that in most cases I can find what I want via the index. I'm also thinking about ways to do a search without resorting to running a local webserver or leaving the browser (one can obviously use grep for searching, but this is not a brilliant user experience). Any suggestions on how to do this would be welcome, btw.
I prefer html documentation because it's parseable / greppable and so that I can view it in links on a low-powered device. It also happens to compress really well. But PDF documentation has its merits too - e.g some PDFs have indexes which are quite helpful. The .chm format has the best of both worlds, but I'm not personally a fan of any of the .chm viewer apps. Your preferred format might depend on your device and interface preferences - I'm on a low-powered device and I want a text-only interface in this case, but to each his own.
In addition to language references, There are also many good free programming books on many subjects available online in downloadable formats. It all depends on what subjects you're interested in.
I was kind of suprised to find that there is no 'documentation compendium' project out there already - I had expected that I'd be able to just download all this stuff at once with a nice index. I did find a program called zeal, but the list of languages/toolkits seemed small and I wanted something more lightweight than a QT app. I've been thinking that once I have my own compendium sorted out I might put it out there for others.