I think the biggest obstacle for some/most is going to be obtaining enough prescription meds (blood pressure, diabetec, etc etc) for the long haul... IMHO, Aside from a very good medical kit, I think an herb garden and knowing what herbs are good for what is also important.
A couple of big bottles of aspirin will come in handy too. Could save your life in a heart attack, limit a stroke and is a great pain killer.
A lot of the need for antihypertensives and diabetes oral meds will vanish if the SHTF ever happens, because people will lose weight and get a LOT more exercise.....