Sadly, I don't think Daisy could ever be walked off-lead unless there was a secure fence and no other people or strange dogs. In fact, as I've posted before, she's a bit of a pill ON-lead! (But we've been working at it diligently, and I think she's starting to get the picture about pulling not getting her where she wants to go.)
She will bolt to the nearest person, car, leaf, dog, butterfly, gnat, bird, ... without a single thought as to where she is going. Her breeder warned me that Cavaliers were usually like this, and she was so right in Daisy's case. We put up a fence in our backyard once we saw that she would clearly never stay in our yard without being constantly on a leash or tie-out. She has a very strong prey drive, to say the least! She loves us, but she is also wildly drawn to every stranger she encounters.
It is very different from the dogs my family had growing up (toy poodles), who would stay right by us with or without the leash, and who stayed in our unfenced yard just because they knew it was the appropriate thing to do! The last two poodles we had were just naturally good on the leash with no training, basically because their choice was to walk right beside us wherever we were, and the leash was just a formality. I've always wanted a Cavalier and I love Daisy to death, but talking about my other dogs does make me a little whistful for a little more impulse control on Daisy's part...
Oh well, you take the good with the bad and I wouldn't trade her for any dog in the world!