The first step is breaking up the turf a bit, so the plow doesn't have to work quite as hard to break the sod into strips and turn it over. A weighed-down disc harrow passed over a few times cut up the turf pretty well.
A few days later, after some rain finally came to moisten the soil a bit, plowing was next. Getting the plow and tractor set-up correctly and figuring out the technique took some time, but soon enough I was turning over rows nicely. Cut about 6-8" deep. My 50's era scanned copy of the "Plow Book" by Harry Ferguson (of Massey-Ferguson tractors) came in quite handy.
I'm was pretty happy with the plowing result. For being such a small tractor, the Gibson had no problem pulling the plow, after I got the hang of keeping the throttle up enough.
After a day of drying out, the field was ready to be disced until chopped up fine enough. I started with the two sets of disks in-line with each other, and gradually decreased the angle between them (more aggressive tillage) until I was happy with the tilth. It took probably 8 passes total over the whole garden.
The end result is almost as good as if I had rototilled it; about 6-8" deep, finely crumbled soil. There are still some small clumps of sod, which I am hoping will dry out and die, and then decompose over the winter and not re-establish as grass.
The next step is sowing the cover crop. I'll be using a "plow down mix" I picked up at the feed store, which is a mix of fall rye, Austrian winter peas, vetch, and rape. It's important that the ground isn't left bare over winter, when the winter rains will wash away soil and leach out nutrients to runoff. I have mentioned the benefits of cover cropping/green manuring in the past, here.
So for next year: crops that are exceedingly tall, require lots of space, are vining or sprawling, those suited for row-cropping, or ones that have a long growing season are all good candidates for growing in their own area. In the main garden (right off the house) I want the crops that I use most often, are the quickest to mature (so I can succession plant better, another goal for next year), and those that require more care or more frequent inspection. I'm thinking that the main garden will be spring/fall crops (2 or more plantings a season) and the field garden will be main season summer crops (1 crop per season). Then I'll switch them each year for a good rotation. We'll see how it goes.