Remember all those heavy stones I said I was carrying? Well they formed this:A nice mowing edge / path to divide the very back of the yard from the rest of the lawn.
Two reasons for this:
One, the 100' extension cord on the electric mower doesn't reach much farther than this, and, two, it is a pain to get under the apple trees to mow the weeds, 'cause nothing else wants to grow under there.
So the plan is to lay a mowing strip for a clear division (done), kill the weeds, and plant ground cover that will thrive in those conditions and not require much maintenance.