This was a great article and seeing as I started down this road (knowing it was coming) many years ago, I thought I'd chime in add my 2c about what skills will be of use in what's coming. I'd urge everyone to look into the landscape design technology labeled as 'Permaculture'. It was invented by an Australian during the 70's and can be summed up as "a landscape system which meets as many demands of the people whom live in that landscape as possible".
I'd suggest finding a local Permaculture Designer and then simply shutting your ears to the nonsense about peak oil, global climate change etc. and learning the basics. Its about how to design a perennial polyculture of plants useful to humans, starting at your doorstep. These plants might be useful in many and varied ways. For instance, an "Illinois Everbearing" mulberry will feed 6-12 chickens solely on its fruit when it is fruiting. Is there another tree/shrub/vine you could add to your chicken yard that will feed the chickens for more of the year? In South Coastal British Columbia the only time of the year I can't find a tree to feed chickens with is late December to the end of February.
If marauders come, odds are they won't know diddly about Permaculture plants! They might steal your chickens, but they are not going to dig up a tree. If you have the space (minimal) and the time (again, minimal) it is probably a very wise time to start an 'edible landscaping' nursery in your yard. Simply get the plants that are most useful in your climate (forget the UN gibberish about 'invasive' plants, we've larger 'worries' than nature doing its thing) and that you might like to eat.
If you are friends with your neighbours, do it all together. Find something that intrigues you all, and plant your useless front lawns with it. I know a fellow who has 300 species of fully dwarfed apple trees on 1/4 acre. He is a Patriot and has been planning for along time. What will one scion of a delicious apple be worth as the bread runs out? What if three neighbours all decided to have a hazelnut lawn instead, everyone shared in the initial buying (you'd be buying bulk trees at that rate) and the harvest was divided with a certain amount of it being 'value added' to pay for the 'rent' of the 'business'?
In your back yard, along with a veggie garden you can have your nursery as a 'fedge' (an edible hedge). You grow fruit/nut/seed/oil/medicinal plants and take cuttings to sell to others.
For more info. go to ATTRA, Goo...er Scroogle 'Permaculture' and then get going with 'plants for a future database'. Nothing beats finding a local Permaculturalist though...but in my experience, you have to slough through a bit of PC gibberish...I know, I've been there!

Thats enough for now
lance