People hooked up to municipal water in the next county over can keep the water lines pressurized for 7 days on generator, sewer is another issue, after 8 days the sewer pumps will stop, supermarkets have 3 days of non perishable foods. People are going to know in very short order this isn't a local event so the rush to shop but in reality, how many people are actually going to show up for work to open these stores the next day!?! Depending on the time of day, looting going to start at least on the second day in large cities. A lot of people are going to see the cascading affect before they are affected themselves. I see First Responder numbers dwindling in a major event probably within the first week given they also have families too. I don't see anything orderly after the second day.
The only thing the government is concerned with after an event such as this is, continuity, assessing, operations and security of the infrastructure such as communications, command and control, response, hospitals, airports, rail etc... so don't expect help!