Do you find that when you stop eating bad food you actually stop craving it?
My weakness has always been pizza in terms of junk food, it's been my 'lazy' food, and while I still have it occasionally I find that since I stopped eating it once a week I actually don't want much when I do have it.
The exercise programme you are going to do sounds great - I also like variety in exercise, it feels sooo much less of a chore.
Good luck