I think sampling parts of typical warmup routines, including stretches, are good. Formula is to Structure and to Vary. Also, make sure she’s hydrated before the workout.
Begin by getting the energy level up. I found jumping jacks (50) works for me. A light jog in place or around the block. Then, some stretches, without overstretching.
If she’s too stiff to stretch to a “normal” degree in some areas, modify the exercise such that she can build on that, and also have a feeling of accomplishment, rather than a let down and consequent loss of focus. For instance, this can be done with a slight bend in the knee, rather than doing a straight-legged stretch, and mixing types of stretching. Awareness of where she is moving from, rather than concentration solely on the end result, is very important.
I would pay attention to trying to open the hips a bit, especially if she lacks flexibility in general. Exercise range of motion of shoulders and waist.
Play it by ear in terms of what exercises would be good for her, and pace it so she can continue thru the workout without collapsing in the corner. Work out with her and make it fun, and then act as coach with her continuing solo. This will build her motivation to work out on her own.
A certain energy level has to be maintained or the body goes to sleep and wants to stay that way in the case of someone who hasn’t been exercising regularly or at all. The rhythm can be varied. When she gets stronger, using light weights on wrists and ankles for some of the workout might be good. Depends. Agree that aerobic and light weight training are a good combo.
Re the punching work. If she has an aggressiveness to her, even playfully, this could be good, if her posture and form aren’t sloppy. However, if this doesn’t suit her nature, I wouldn’t push it.
In terms of diet. Someone I know just started the Belly-Off Weight-Loss plan via Mens Health. I know, it’s for guys, but I tell you, this diet is awesome! You don’t starve. I think a woman could make adjustments and emerge more slender and well-nourished, also nice-tempered (as opposed to the *****iness that often results from feeling radically deprived, or always hungry for something). Anyone who is interested in taking some weight off and not being made miserable in the process should take a gander at this plan.
Cody