Something I haven’t seem mentioned here yet are nuke power plants. In particular the spent fuel pools that require power to circulate water cooling the rods. While I sure hope that the military, FEMA, or the utilities themselves have plans to prevent meltdowns following a major grid failure I have never read anything more than each nuke power facility has emergency generators with anywhere from a few days to a few weeks worth of fuel on hand. The potential for 104 Fukushimas in the US exists if those emergency generators can’t keep running in a grid down scenario. We can recover from almost anything, but not 104 Fukushimas.
There isn’t much I can personally do about the nuke power plants (other than pull out my nuk alert so as to at least know if there is a radiation issue on top of everything else) and so in the days following an EMP, I think I would focus on trying to help organize neighbors for mutual aid and protection. Being few take preparedness seriously, for most of us, organizing the neighborhood before TEOTWAWKI is just not possible. Additionally, few of us are in a position to go it alone either. In my case this is why I picked a BOL in a small hamlet rather than in an isolated setting. There is safety in number so to speak, and collectively a much deeper set of skills. It is also why I picked a neighborhood of farmers and working class folks with practical skills rather than a higher end setting of second homes for urban folks.