I also have a total gym, and as far as lower body you can do squats, on it, and you can do legs too, what I mean by that is that you can work your inner thighs and your outer thighs, I would recommend viewing the video that cam ewith it, as well as looking at the exercise uide that cam ewith it too. If you need any additional help just email me and I will help you.
As I read peoples posts and OPINION's I find it very discouraging, If you can afford it then GOOD for you, do not let anyone discourage you from anything, I personally think that joining a gym is a waste of money and time and a waste of peoples opinions. It is only good for the sauna. I plan on getting one of those. exercise equiptment is fairly cheap these days all you need is the room.
Good luck to you on the BFL, I am on my first week, going on my second week, as for cardio, sometimes I use the treadmill, it has a tv on it
, and sometimes I use the firm tapes, and sometimes tae-bo, next will be the total gym, just use what you have and make the best out of it.