open source mesh networks are freely available already. https://libremesh.org/ This can be used by neighbours to communicate between themselves, kind of like CB radio but using laptops/desktops/wifi on cellphones etc. Range would be limited but as more nodes connect to the mesh, the wider the geographic coverage. It won't give you access to the WWW or greater internet access unless one or more of the nodes is configured as a gateway and of course, the internet itself needs to up and operational. Even without the internet, mesh nets enable local groups to communicate, securely and reliably between themselves.