I hate to be a voice of pessimism, but something that's not considered is nuclear power plants. When the shtf, the grid will fail, when the grid fails 200 some reactors will meltdown, game over.
Putting aside nuke plants, once fossil fuels and chemicals are done being spewed into the atmosphere, the earth will rapidly rise 2C, with the abruptly changing climate, it's going to near impossible to observe, learn, and interact. Again, game over.
I've found preparing for shtf scenario is so five min ago. Reconnect with plants, love your fellow man, do what you can to enjoy your life with the pursuit or excellence. Sorry to be such a bummer. Perhaps the next species that comes around in about 10 million years will do a better job.