Ceflahexin seems to be the one to take for the current batch of coughs going around. I would be nowhere on this stuff if the net blinked off though. I have to look it all up in real time when something comes up.
A lot of this though, has to be skills, knowhow, connections, and attitude based. If it is just about your stuff, then your welcome runs out when your stuff runs out.
Language and cultural skillsets seem kind of immaterial unless you are a mobile group going through otherwise hostile areas. They do come in critically important with respect to trade with the outside world, especially since the first levels of return to a functioning social economy usually involve trade caravans of some sort.
Physical attractiveness, hygiene, charisma, they count for more than people want to admit. I noticed that a while back when I was in "backwoods mode" and morale/treatment went a bit downhill with some people. One of the mods here is like a born diplomat. Has the in-person charisma to win people over who would never give me the time of day.
Mechanics are always in high demand with these kinds of things, skilled welders, electricians, plumbers. Any kind of construction trade actually. Farmers tend to be multi-talented people. I don't think there is such thing as too many construction guys or mechanics, but then gunsmiths, realistically, what is not common knowledge, maybe one or two per localized retreat network.
Remember that in the depression era, everyone worked, but what saw reduced wealth production was the fact that there was not much around to amplify that work. Not everyone had good farm trucks, tractors or combines, so the poverty of having to farm with animal power was evident around. Likewise, power tools were rare to begin with, but those who had money had access to sawmills, thus faster lumber production, higher grades of finishing on boards and trim. They had the ability to cut lath, which meant they could do lath and plaster walls - 100 year stuff as opposed to open interior walls or blankets hung from brackets in the ceiling. That, or as cheap as fuel was, it was still cost prohibitive for a lot of people.
First basic rule: If you work, you eat. Nobody who works or is willing to work gets denied the basic meals, a place to sleep or realistic access to a hygiene facility. It's just not that hard to build a bunkhouse and if nobody in a retreat can understand the concept of building and maintaining a basic bunkhouse, then it's not ever going to be a successful operation.
Places to stay: You filter things from camp to camp then finally the survival retreat. This is not any different from working your way up in the neighborhoods in a city. People can either gentrify the neighborhood (make gradual but permanent improvements at the camp) or move to a better one. The thing to be careful of is investing efforts in a situation where it is constantly bleeding its wealth production out in rent, taxes and interest. These things will never work when the full time residents are having to pay for the lifestyle of off site landlords who in turn are paying ongoing interests to the banks. Likewise, utilities need to be paid when necessary, but in reality, you don't want those bills at all. Off grid power system, wells, internal garbage services if possible (landfill, burn pile, composting). Sometimes just reality catches up with that and you have to pay for stuff, like dump runs, internet and phones, heating oil and propane.
If you do institute a rental model, then residents need to have some substantive input on where that money goes. I am not there to chop firewood, chase chickens for eggs, sort trash and build stuff for the "right" to pay rent that cover's someone elses's kids ivy league college tuition, or their new car, or their annual trip to Hawaii. If that's what it's about, then I might as well just go back to the corporate world and get the best deal for myself that I can hustle.
That's the big difference between the survival retreat setup and say, regular rental property. On the survival retreat setup, the part timers financially support the situation to some degree in return for the right to occupy space there when SHTF, or whatever. People who frequently travel and then use the place as a home base of frequent stop, that works. What will not work is the full time people trying to develop the place while financially supporting someone on the outside.
There is no rent and no wages on the basic survival side. Beyond a probationary period, once a member, it is expected that what you pitch in is permanent, sweat equity to co-ownership. Do NOT pull that "grapes of wrath" sharecropper stuff. Americans ought to not put up with that.