I'm also thinking of giving my lot supervised free range time on the whole property, especially now that we're going to restrict their space for six weeks to help the grass grow.
However when I've tried that in the past they stayed disciplined for a day or two and then they just get overexcited and dispersed everywhere. This made it difficult to supervise them, and also after two days the bucket of corn to make them come back lost it's interest and I had to go carry them back one by one.
Maybe I didn't insist long enough and after a while they would think of staying together ? Also we used to try it in the afternoon when we were working in the garden, but maybe it's better to do it at the end of the day so that they would want naturally to come back to the coop when night settles in?