Well, that's the reason for the question. Stated another way,

At what point (stated in acreage or square feet) does gardening cease
to be fun and therapeutic?

And while we do intend to grow some melons, we want to intersperse
them, and everything else we plant, with suitable companion plants.

While information on companion planting is widely available on the
internet and elsewhere, my reasons for posting here are to hear the
experiences of real people.

As to the agriculture exemption: My first objective is to find
experienced people's view on the largest size garden that two or four
people with modest mechanized resources can reasonably hope to plant,
tend, and harvest.

Let's say the collective answer is: "two acres". In such case, I will
plant EIGHT acres in grass and lease it for hay cutting. Thus, I'll
still have the 10 acres elegible.

Thanks!
Vernon