So maybe that dual power needs to involve some dual infrastructure, yeah?
Start a mutual aid group who fronts as a tech support collective and gradually install mesh routers and nextcloud instances throughout your neighborhood to make it redundant in case of internet “outages”
I think the issue would be the physical infrastructure for local-to-local communication. Fiber costs over $25,000 per mile to install (probably a ton more if you want some sort of a secretive system that doesn't get any permits), so the lower end of connecting Philly and NYC is like $200k.