I have to admire your determination! That's a lot to change at once.
I can understand wanting to change everything, but at the same time, you might be setting yourself up... And why do that? Maybe change things one at a time.
I wouldn't be able to handle that many changes at once, myself. Especially the quitting smoking--that's really, really hard for most people, and it was for me when I quit. Maybe it will be different for you...
If I were trying this, I'd quit smoking first. Then I'd start with the exercise (and start slowly--no drastic, killing workouts) and weight loss program.