Damian,
Your design ideas are good. One thing that does speak to me is the size of the yard. It's location is almost too far for a garden. Also start small or a garden that large, especially without a tractor, will become absolutely soul wrenching. Fence it off temporarily and run stock until you are able to grow your plot or plant something perennial. (Food forest maybe?)
I have found that the gardens inside zone 1 really do make a lot of sense, even if it's not the "best" location at your disposal. Aerial maps only show so much of course.