Our front yard is fenced..... but each side of the house is open to the back which is not.
With Jaya.... I trust her implicitly - she listens very well. I watch her like a hawk though, and anytime she gravitates to an area that she shouldnt be in, I just call her back. I am very lucky with her because she has no interest in other people or anything outside of her "family" which is Jenna, me, and my hubby.
Jenna on the other hand
is untrustworthy.... lol I can't trust that one at all. I keep her on the leash, or occasionally let her run around with her leash - its easier to catch her.
But what we do is, my husband stands guard at one side of the house, and I stand on the other. And we just stand there prepared for anything, and loaded with their favorite and forbidden treats - to lure them back to us...though we have not yet had to use them.
For longer playtimes outside, we bring out their xpens and attach them together and make a big circle.