JTP,
I agree that respecting her and her religion is a good idea. I hope she believes you when you tell her you will do just that.
I am not being pessimistic, just realistic, for your family may be emotionally and spiritually more in tune than mine, but here's what happened when I did the same thing:
They looked at it like I was slapping them in the face. In their eyes, if I did not completely come back into the JW religion, I was going against God. I believed differently. They could not accept that we should just agree to disagree the way that I did and the way that it seems like you are intending to view it.
Having said that, however, the attitude that you are approaching your mother with is about as fair as you can be to her. I wouldn't change your approach, just don't expect her to say, "OK honey, that's all I ever wanted." Hope for the best but be prepared for further challenges from her.
Brad