Ryofire wrote:
....or she will be doing too little, and end up gaining unwanted weight....
So she would also be increasing her calorie intake? Because if she already walks, then any kind of added training won't cause her to gain weight, it would just be less effective at helping her lose weight.
Personally I'm a big fan of strength training and cardio that really uses your muscles, so bodyweight conditioning, plyometrics, etc. Think of burpees, the Insanity series, etc. I think she should try doing as much exercise as she thinks she can, then backing off a bit if she feels too tired during the days....