Living in a country with poor internet access, my methodology has been:
Offline Wikipedia
HTTrack for any wiki I found useful.
Calibre (for the l*gen files)
A dictionary software.
A backup full of the software programs I normally use (VLC, Office, Linux ISOs, Firefox, ...)
At the time, that was pretty much it. I did not have any phone, and only a few apps are useful online. Maps being one because of the smaller form factor and the GPS module. I went to Cuba once, and the only use I got out of mine was maps, camera, and Spanish dictionary.