Earlier quoted context omitted.
Wikivoyage, Wikitravel, I can never remembered which is the most up-to-date. There are some offline apps for them on iOS (okay not great) but they've worked for me abroad a few times. The ones that come to mind are Turdus and Voyageur, both free.
I have Wikivoyage's XML dump saved on my laptop. Recently I arrived in Berlin and realized I wasn't sure how to get to the city from this secondary airport in the best way, so I opened my computer and one easy incremental search in Emacs later and I knew just what to do...
[0]: https://en.wikivoyage.org/wiki/Wikivoyage:Database_dump
[1]: https://en.wikivoyage.org/wiki/Wikivoyage:Offline_Expedition