I'm considering even creating a dial-up (yes, V.34 modem!) line somewhere near to Russia, to offer a side channel with text browsing, news, IRC and email. For when things get really, really bad (they will ...)

Before you ask: yes, dialup works on modern networks if the codec is G.711 (uncompressed). Most public phone network is this way because fax is a thing, but some bulk carriers or some enterprises use compressed codecs.