We could make it a long time. We live in the country so we have lots of food around (pantry and deep freezer usually full), a generator (though we don't currently have much fuel on hand), 1500 gallons of fresh water at all times in a holding tank and a well that we can run off the generator (and we could get water out of the creeks and ponds and sanitize it if we had to). We have a rifle and shotgun, though we're currently almost out of ammo. The main problems I foresee in a disaster that would cut us off from the rest of the world would be me running out of Zyrtec (have a couple months' supply, it keeps me from having constant hives that could potentially cut off my airway), and not having enough ammo. We're ok for water, food, and heat (use a woodstove almost exclusively and have used it for cooking on on many occasions during extended power outages.) Having a supply of gas and diesel would make things nicer, and having more ammo would make hunting much more productive. I have enough garden seeds leftover from gardening last year that I could garden indefinitely (I could save seeds from crops from year to year) and we have an orchard (apples, plums, asian pears, cherries, kiwifruit, strawberries, raspberries, rhubarb, blueberries, lingonberries) along with native foods we could gather from our forest. If I have twenty or thirty gallons of diesel, I can keep my greenhouse running through the winter and keep cool season crops growing in there. We have chickens (9 hens and a rooster), so we have plenty of eggs to eat and could let the hens set nests once in awhile to get chicks that would make some fine eating after they grew large enough. I even have a banana tree, pomegranite tree, eight coffee trees, and three citrus trees (lemon, lime, orange) growing indoors. A neighbor has a bunch of goats, so we could probably find a way to barter for a breeding pair and end up with goat's milk and kids to raise for meat. We plan on stocking our pond with trout fry in the next year, so we'll be able to fish on our own place in the not too distant future.
Cliffnotes: All in all, we're much, much better off than most people.