Just another note. Be very aware of how much land you are 'bringing into' the garden and the amount of work that this implies. Large areas, even relatively unmanaged ones, involve a lot of work. I have a friend who has a three acre very managed woodland-style garden. She spends 40 hours a week tending it.
I don't have that kind of time to work in the garden (I have children and a job). I have to restrain myself from cutting more beds that need weeding: it's great to think big, but big can mean lots of weeds. Tasks I have to do every year that maybe wouldn't happen in smaller gardens:
Nettle control in the windbreak/woods; dock control in the orchard; hogweed control everywhere.
Once a year hiring a heavy-duty brush cutter to cut the orchard grass, then a week later raking it and putting it as mulch around the fruit trees and new trees in the woods.
Strimming between growing shrubs.
Keeping areas around hundreds of newly-planted trees grass/weed free so that they can flourish.
Dealing with large numbers of trees. A lot of ours are mature and they do fall over/lose branches. One time my husband had to cut a path out of the gate with a chainsaw so that I could get the children from school.
Trying to find time to mow a large area of lawn between weather and schedule. If left too long/mowed too wet it can look dreadful (as at the moment).
Machinery to obtain/maintain: chainsaw, strimmer, ride-one mower (expensive to buy and incovenient to service), buy or hire chipper, hire or buy log splitter, hire brush cutter, hedge clippers? The machinery has to be better quality/more robust than you would use in a small garden. A cheap chainsaw will die in no time. Ditto strimmer, etc.
Composting on a large scale. At the beginning of the summer I make sure that I have three large cube compost bins empty because the grass clippings (plus scrunched newspaper/cardboard) from the lawn will fill them in no time.
A full weekend (at least) each year for the whole family of splitting wood for the woodstove. This is on top of Husband's work with the chain saw to cut manageable lengths.
Tips to help deal with the garden. Use mulch fabric as much as possible to reduce weeding. Buy a chipper or hire one once a year so that any stray branches can be chipped to make mulch to cover the fabric. Get a woodstove once you have trees big enough to burn - if you decide to plant enough trees that this will make sense.
That being said: we love our garden and wouldn't swap it. It's just turned out to be more work than we expected, and we've had to adjust our expectations about the amount of work and just how pristine it can be.