The first thing that I would do is to try to make it tie in with your outdoor living.

Farmer's have this field over there, that field over here, which works fine for farming. It looks like you may be looking at your garden site like a field of crops. Would'nt it be better to tie it to the house, to a view from the house, and to bring it into your living space rather than just ... out there in its own space?

The walkways are the strong visual that can enhance or degrade those effects. I'd look to plan the layout of the walkways, at least on paper, and start to build from there (keeping in mind solar orientaion and other horticultural conditions that might come into play).

The next question that I would have is whether having a patio that far away (the hill)from the house is really going to be useful. It looks as if you might have a view that you think will make it a destination, but I would seriously think about how you plan on using the patio and if it might not make more sense to keep the patio between the house and the garden - access to kitchen, bathroom, arriving guests (expected or unexpected).

I think that when there is a lot of land there may be a tendency to look to spread over it to help eat it up, but if it really does not work with usability it might be regrettable.

I agree with laag that walkways/paths are a good place to start. I have come to see paths as a great way to define space - a way to lead your eyes as well as your feet. If I was starting over, especially in a bigger space, paths would be somewhere near the top in the tools that I'd use to help start the layout.

As for the patio on the hill... I wonder if patio is maybe the wrong word for your intentions? Perhaps look-out might be more what you mean? Where I grew up, there was a hill on either side of the house and the rocky hilltops were favorite places to sit/rest and look down on the 'world' that was the house and the more domestic areas around the house. Perhaps something like that is what you mean? - i.e. have a functional patio near the house for outdoor dining and lounging but have a seating area on the hilltop where you can see all your world at a glance. It's an amazingly peaceful and comforting thing somehow to be able to view your home from that perspective. So I think it's a good idea to have something there on the hill but put the high use patio near the house where you will have close access to kitchen and other such facilities.

Take you time, day dream but also ground it in practical stuff like just how much maintenance you can cope with and build that into your plans too. Have fun - I envy you the space!

For what it's worth, I agree that somehow connecting the garden space to the house will make it more likely that it will be used and even (as Woody suggested) whether it will be maintained. I think that walkways are a natural way to do that, so even if the garden area itself remains where you've put it, think about some way to create a path that leads directly to it from the house. For this same reason, I would also suggest having some sort of outbuilding down there to contain tools and materials - that way you are not always trekking back to some other existing building when you need something. You can easily incorporate a nice shed into your garden design.

Also, the "road" is going to be tricky - do I understand correctly that it will completely separate the garden by cutting a swath through it? If so, my first thought would be to NOT try to include the area to the left of the road (as shown in your schematic) into the garden. The road is wide enough, and needs to remain open to allow for equipment to pass through, that it would be very difficult to make the two sections appear part of the same garden.

I sure love the inspiration garden - wonderful that you have the space to do something like that!

Thanks everyone! I appreciate the input. To clarify a few points:

As for the "patio" on the hill, I guess a lookout would be a better term for it, though we'd like to include something more permanent there, such as patio bricks to set chairs on. We have a few lawn chairs up there at the moment, and it's very peaceful to sit up there, drinking coffee first thing in the morning, looking out over the field. I wouldn't expect it to be an area used for entertaining, since it is so far from the house. Instead we were thinking of building a deck off the house, extending it into a low deck over the septic tank area, that can be moved if/when access to the septic is necessary. Planting anything over that spot would be pointless, as it would get dug up, not to mention that even the grass doesn't last long over the concrete slab underground once the heat (and lack of rain) of July rolls around.

Planning the pathways first is a good idea - I'll get started right away! I am excited that we have the space to play with, but it's a bit daunting and staring at the large expanse of lawn, it's kind of hard to imagine what it'll look like when it's finished. It'll certainly be a challenge.

If you've planned a large garden, I'd love to see some photos and get any tips you can offer! Thanks again.

I also LOVE the picture that you are thinking of re-creating. However, before you get started you might want to search and read about meadows, prairies, and wildflowers. There are some forums here on Gardenweb too. I am no expert on this, but it might be something you could use on all or part of your great expanse of land. Some people kill off the grass with an herbicide like glyphosate, some people do a controlled burn before planting natives or seeding wildflowers. And then I think you have to mow or burn the meadow periodically to re-fresh it, so to speak.
Good luck in whatever you decide.
laurie

Looking at the Google Earth picture, I got this weird idea:
(If it was my yard, and if I knew someone who owns a tractor, and if I could afford it)...
... I'd dig a large pond South-West of the hill - in a shape that "curves" around the foot of the hill. With the material excavated from the pond's site, make another hill SW of the pond. Plant a group of trees on Hill 2. Make a pathway from the house that branches towad Hill 1 and toward the pond, have that branch perhaps circle around the pond (leaving enough space for waterside gardens) or end in a landing deck... then start adding shrubs and flowers, trying not to block the views from the seating areas, but to frame the views with interesting shapes and colours.
Now Laag and other wise people, what's my budget for this sort of project? Supposing the guy who owns the tractor is young and eager to test his machine?

Just a word of caution per the septic system. Never ever ever plant anything other than grass over it, esp. trees. The roots will eventually grow into it and destroy it and cost you thousands and thousands of dollars to repair it (re-doing it, moving the tree or trunk, etc).

I love your inspiration photo! I, too, would suggest starting out with the 'hardscapes' of your garden and work around that. It's a lot easier to move plants around than a walkway.

You've asked twice for others with larger projects and properties. The thing is that those who have them may not drop in and see your request. A couple of past threads flashed in my mind and I'm off trying to dig them up.

here's the first. I don't think it's as large as your own and the context is Ireland, but if you are simply looking for ideas, ways of thinking through the process, there may be something of interest...

I think I also remember one down in Georgia? that was also on about 40 acres and also about a gradual development process. I'll see if I can figure out the search that will bring it up...

Here is a link that might be useful: Ideas from property in Ireland

The link below is about a specific problem from a zone 5 gardener in west NY. The issue is that her home is on 25 acres of "mostly field" and there's a need to develop a windbreak. Maybe raises some questions to ask yourself in your UP situation?

Here is a link that might be useful: Designing windbreak

Thanks for the links, wellspring! I'll check them out right now.