As far as the cities go I don’t think they will wait too long before moving in. Maybe a few weeks to 2 months after SHTF. They have to find that critical balance. Wait just long enough to starve them out and do away with the weak but not long enough for the survivors to get too comfortable and start organizing. I’m not completely sure on the rural front. My best guess is that they will nationalize food production and start seizing property for federal farms, but I believe that will come much later after they have gained control of the cities. They will probably re-educate the city folk and those in the detention centers and get them on their side for seizing property for food production and the good of the people.