I remember a late 50s/early 60s TV movie where the family with the fallout shelter was having to force their neighbors away so they could close the door...
Seems to me the best long-term solution is to possess a key skill that will be considered so valuable that others will leave you along in order to keep you around. Of course this only applied til the point where their empty bellies start to do the talking...
I’ve looked into making insulin from beef or pork pancreas, like they used to do. Surprisingly, it is not that difficult in terms of basic tech.
Not sure that that’s valuable enough, though.
For a laugh, look up the song “Black Powder and Alcohol” by Leslie Fish. She was concerned about the collapse of everything (two decades ago now) and wrote a song to teach people two basic skills- black powder and alcohol.