I've tried walking around the neighborhood in the evening, but it's not too convenient. Particularly negotiating night critters and other "night owls": the former ones creep me out, the latter ones can be spooked by a tall guy coming in their direction...
What seems to have worked fairly well is taking a walk in the greenbelt in the afternoon. It's quiet enough that I don't have to focus so much on where I'm going and so I can lend a bit more of my mind to meditating on the mysteries. But I'll need to give it more tries to see if I settle in this habit.
Praying the Rosary sitting still doesn't quite work for me. Somehow, I can't hold the same position for too long without being overly preoccupied with it. If there's one place where I can say the Rosary in the same position is in church, at least sitting down, but I believe that kneeling too. I guess it's because of how other senses are catered to in a sanctuary: our vision is blessed with holy images and architecture and our hearing enjoys silence, inviting that gentle whisper (1 Kings 19:12).