How much is too much exercise when you are eating between 1200 to 1500 calories a day? For example, if I were to complete a p90x strength training workout which is about 60 minutes and an ab workout around 15 minutes, is that enough of a workout? Would adding another 60 minutes of cardio be reasonable or excessive?
I think a moderately intense workout between 30 min and an hour and a half would be perfect. If you go overboard then you are really over working your body and by that point you know what your limits are.
I think you should let your energy level be your guide. I would do my normal activities and then if I still had energy afterward, I would put that toward a workout. When you are trying to lose weight, and eating less, it's probably best to limit your workouts to less than an hour per day or up your calorie intake.
I would maybe suggest eating a little more on days that you really workout hard. That way you wont run into any problems.