Another HNer mentioned Costa Rica's internet connections during power outages, hence my question: https://news.ycombinator.com/item?id=28169281
There's also good LTE (as a fallback) in many villages that cater to tourists, but coverage is spotty as you get more remote.
Again I don't really see power outages last longer than an hour or so, but my laptop manages to run for about 2 hours with a 4g modem in it. I used to be able to go even longer with an extra battery back when laptops still had those -- So really as long as you're not lugging around a UPS and desktop for some reason you should be good for at least that much time.
If it's out longer than a day I pretty much just pack my stuff and head into the city. I recognize most people don't really have this kind of luxury with the kind of work they do but I specifically worked my way to this point where I can afford to do this and maybe if you stretch your imagination in terms of possibilities you can too