Let's do some apocalypse, shall we ?
How much of the population was wipped out ?
This will determine what kind of settlement you can find. The more apocalyptic it was, the more disperse the groups will be.
How global or pinpoint was the destruction ?
This will tell you what chance you have to find large, organised, possibly almost intact town/city.
Did the apocalypse affect only humans, only living beings or was it also a global destruction ?
The more "global" the destruction, the less likely it is that large infrastructures (like dams, nuclear plant, power station) remains untouched - hence reducing the probability of electricity being available.
A suggestion: the apocalypse was cause by a massive solar flare, which roasted a good chunk of the population, toasted everything which was high tech. However, as a side effect, earth is now constantly generating radio-wave of various level and intensity. The radio-wave soup allows to have wifi and radio communication with very rudimentary, mechanic based system: instead of having to emit something, you just tweak the ambiant waves.
Of course the more accurate you want the information, the more performant and high tech becomes the equipment. And because it is free flowing, you have to be careful to who could be listening.
That could be a fun way to have radio system without much electricity and the whole infrastructure required (servers, antennas & such).
And maybe there are some strange immaterial creatures living in these ocean of radio-wave.
What about some weirdos who decided to apply metal sheet straight on their brains so they can listen to the Signal...
Nothing can stop the Signal !
