Dancing is incredible exercise. I did a little dancing a couple of weeks ago and I was sore for a couple of days afterwards. And Steven I am sure there is video somewhere....
My wife has a couple of friends that come train with her that she introduces to exercise through Yoga for Regular Guys and some dance videos she has. That gets them moving then next thing you know she has them sled dragging and doing intervals.
I was talking with a young lady in a similar position last week and I told her as long as she looked at it as "diet" and "cardio / exercise" she would fail. As has been said whatever it is that she engages in has to be fun and part of her lifestyle.
Best of luck.
What we think, or what we know, or what we believe, is in the end, of little consequence. The only thing of consequence is what we do. -John Ruskin