I have a feeling that there is a lot more to this scenario than what is being shown to us; keep that in mind. Considering the lack of maturity at the heart of this thread, I doubt the family is comprised of a bunch of completely unreasonable people who expect too much from a son that lives in their home. It would be foolish to assume you've learned any hard truths about the OP's family in this thread considering you are getting a single biased side of the story.
The smart and responsible thing to do would be to have a civil conversation with your family and make them aware of your intentions. If you do not care to keep ties with your family, sure you can blind side them and leave without any notice, but realize how that looks to them.