I have considered the possibility of a communications/internet blackout and its potential effects upon the crypto world. At one point I tried to stir up some interest in running Hive transactions over AMPRNet (Amateur Packet Radio Network or what is also called 'Network 44') but no one seemed interested in it. There are a ton of IP addresses available for it also. They are 44.0.0.0/9: For USA subnets and 44.128.0.0/10: For the rest of the globe. All available via HAM!
The one item I try to recommend to folks for 'prepping' is a hand (or foot) powered device for recharging batteries and/or battery banks. K-Tor produces some nice ones if you are ever interested in looking at them.
I am not much of a prepper myself given that I took Terence McKenna's advice long ago and mostly 'live as if the apocalypse has already happened' but that said... the biggest factors are psychological ones and having some routines (especially with rationing supplies and maintaining morale) already in place long before any 'weird stuff' happens.
I used to love telling people who mentioned 'survival' or anything along those lines... that when living in a dangerous scenario... or one where resources are a scarcity: Survival better be a fucking habit.