Your great success is very encouraging! I'm not sure if I could write a book, but the results from consulting and programming are very impressive for a first attempt.
I'm in the middle of making the jump myself, and am currently paying that $4000/mo for our family of two. Did you simply save up enough to live on that for a few months to make more of it? How did that work?
Thanks for the inspiration and congratulations again on your successful year!