I should really add craft skills to the list of tradeables... Just being able to create some minor bits and pieces... if you have a source of bamboo, willow, even palms, basket-weaving isn't such a useless skill to have under your belt. As plastic becomes unavailable, just having a sturdy way of carrying items is very useful. Making and repairing craft items is a skill in itself, and if others can't do it, you might as well...
I am trying to find a couple of non-electric (ie manually operated) sewing machines - ones with foot treadles, rather than a hand wheel. Although... a little bit of ingenuity, and that isn't an insurmountable, just one that would require more work to adapt in the short term - for less hassle in the long.
I get to the subject of sewing machines because of reading one of Richard Feynman's books; he was a physicist, winning a Nobel Prize amongst others, and a social commentator. Apparently, he had a habit of touring the poor areas when he was visiting foreign countries. On one tour, I cannot remember which country, the taxi driver (ethnically African), showed him two women (ethnically Indian), who had bought a sewing machine and were doing quite well doing small repairs. His driver asked him why Indians in the country were doing well, while Africans were doing well. Feynman hesitated, not wanting to be a racist, but eventually gave the opinion that culturally a group that placed value in hard work rather than luck (or words to that effect) were more likely to succeed in the long run. The driver agreed, and said that he was going to buy his own taxi and really succeed - once he won the lottery... The point of the story is that you can't depend on luck for success - you have to do a lot of hard work.
If you want to succeed PSHTF, a lot of preparation and work is required - you can't rely on luck.