There's plenty you can do to prepare for SitX besides what has
been mentioned here. Go get yourself a Peterson's Field Guide
to Wild Edible plants and get studying. Then take the next step
and try making teas for your self with things like pine needles,
spicebush, black birch, wild mints.
Then try spicing up your salads with common yard weeds like
dandelion, plantain and chickweed. As you feel more comfortable
with wild foods you'll find your self out digging up wild carrot,
evening primrose and burdock root. Even in cities you can at least
learn your weeds, many of which are edible and very good for
you.
You can practice different forms of firemaking in your back yard
or basement like bowdrill, flint and steel, magnifying glasses etc.
Kids really love fire for some reason ( I must be a kid then).
I think meditation is also a good idea in that you will need patience
and a clear head to survive if things get bad.
Try fasting, you won't get to eat everyday in sitX and you can
accustom your body to those changes.
Of course study books or research the web for subjects like
obtaining fresh water, improvisiing shelter, permaculture
gardening, trapping, hunting, making clothes, emergency medicine.
That should keep you busy! Good luck to all and prepare now.