How about simply prohibiting riding mowers? I mow somewhat under an acre, largely sloping, with a push mower (i. e. powered blade but I have to move it). Letting it go back to jungle is not a reasonable option, but I would have to spend that much time walking or jogging anyway, out of concern for health, and this is better upper-body exercise.

But I see my neighbors on both sides riding on their machines, burning several times as much gas to do the same job, and getting plumper. I suppose it's all a matter of degree, but still...

Peter