If you forecast that your supplies will be very slim on day 5, and you haven't left for greener pastures by day 3 or 4, then the the worst case is already unfolding. GTFO before the worst-case ever happens.
But in that worst case: One can call on someone else for help. This is one of those situations where it's time to cash in some favors, and/or where it pays off to always be friendly and helpful with to the neighbors even if they really seem like a bunch of assholes. (The time to start being friendly with the neighbors is right now, by the way.)
(My own backup plan only keeps me rolling both semi-comfortably and independently for about 24 or 48 hours without power in the winter, so I'm leaving after the first night or ASAP. I don't have the complications and niceties offered by something like an F-150 Lightning, but finite resources remain finite no matter their form.)