A few caveats for our place, but I'll share our experience - we don't provide 70% of our own food - not even close. However, we do eat a lot that we have produced, and trade some of our produce and eggs for other things. If I were guessing, I'd say we produce 100% of our late-summer and fall veggies, 50% of our veggies through the winter, almost none of our fruit (yet - the trees are still young), and 100% of our eggs. We don't currently produce any of our own dairy or meat. We also don't own a tractor, so things like lawnmowing, fencing, and snow removal take us a lot longer than if we'd had one.
We moved here 8 years ago, with a couple of cats and a couple of dogs. We've got 10 acres with a run-down house that was vacant and untended for quite a while (more than 5 years) before we bought it. The house was solid, but needed some immediate repairs, and the yard and outbuildings were a mess. There were no fences when we moved in, and the barn was not usable, so we converted a large granary into a barn of sorts.
Our first year here, we grew a massive garden, and also got three more cats (for the barn), 50 chickens, two alpacas, and 4 goats, one of which was in milk at the time. We grew over 500 lbs of potatoes, and similar amounts of carrots, beets, and squash, much of which we donated to the food bank, because we had no idea how to preserve it. I also wore myself out trying to preserve a years' worth of tomato sauce while working around a full time job, learning how to milk goats, and dealing with the learning curve on chickens, alpacas, septic tanks, and cisterns. In retrospect, I'm surprised we didn't give up and move back to town. Oh, and I discovered I was pregnant shortly before chicken butchering day. That sucked. I still don't cope well with that wet feather smell.
So, that first year, while dealing with the learning curve on 1) chickens, 2) goats, 3) alpacas, 4) gardening, 5) orchard planting and management, 6) farm systems (septic tanks, water pumps, fencing, etc), 7) home renovations, 8) food preservation, and 9) local culture. I'd say I was putting in about 60 hours/week (around a full time job and commute), and my husband was putting in 90+ hours/week. I don't recommend it. We ended up selling the goats and alpacas, and my husband has now instituted a rule that I am not allowed to introduce more than one new species per year, though he's a little more flexible on the flora than the fauna - I think I snuck in three new veggie species last year.
Now, eight years in, having gotten past the learning curves on most of the big stuff, we probably put in about 20 minutes a day in winter (livestock and pet management, plus some planning), and maybe a couple-few hours a day during the growing season, much of which is in hand-watering new trees during dry spells, as well as putting up the summer produce (beans, raspberries, etc). There is always the big planting push which takes all of our attention for a couple of weekends in the spring, and the big harvest push, which takes up a few weekends in the fall.
We normally grow 600-700 onions, 200-300 (+) pounds of potatoes, 80-100 winter squashes, 40 pounds of carrots, about 30 pounds of beets, an unknown amount of green beans, but enough to feed 4 people a generous serving every day or every second day from when they start until the frost gets them, plus a bunch for the freezer, enough tomatoes for fresh eating for four people, zucchini out the wazoo (when we have enough for the freezer, we start feeding it to the chickens), 20 + pounds of parsnips, and various soft fruit (raspberries, strawberries, currants, etc). There are also the miscellaneous things like asparagus, rhubarb, chard, sunflowers, and such that are nice during their season, but don't really produce a large amount of our diet. We also get a lot of eggs, but there is a glut in the spring and summer, and few in the winter. I make all of our own jelly and jam, mostly from foraged berries and crabapples. We still buy a lot - all of our grains, dairy, and meat, most of our legumes, fruit, and some vegetables in the winter (particularly brassicas, as we struggle to grow these, and I love cabbage). We also buy feed additives for the chickens, and food for the other pets (cats and dogs).
The upshot of this is that it is hard to predict how much time you will put in on any one thing, but I can say with some certainty that it will be at least three times as much as you expect for the first year or two you do something you haven't done before, and that each species of animal counts separately, as do the garden and orchard, as well as preserving. If you haven't dealt with rural life before, add in more time for learning household systems (septic, for instance, or wells, or wood heat), as well as adjusting to rural life, where things can be very different from the city in many aspects, from how you shop (possibly infrequently, if you live far from town) to how you socialize. Once you are over the initial learning curves for each thing, it really gets a lot easier, and the amount of time things take drops dramatically.
If every person in your family is 100% on board, you'd still be better off to start with just the orchard, the chickens, and a garden that is about 1/10th as big as you think you want, at most. Once you have those things down pat, think about adding in the larger livestock; it will save you a lot of heartache. That is assuming you're not commuting very far to your job, and that any homeschooling takes up a small part of your day. To be honest, with home renos, a job, and homeschooling, I would consider just planting the orchard and a very small garden for the first year.
However, hindsight is 20/20, and if I had it to do all over again, there's a fair chance I would still bite off way more than I could chew. It's hard to overcome the enthusiasm, and the sense that I want ALL OF THE THINGS, RIGHT NOW, especially after a couple of decades of dreaming about moving to the country.
Good luck to you :)