I am pretty much in the same boat as you. My wife is in the same situation. She calls it "her faith" but she does not fully practice it. Marginal believers are harder to understand than hard line JWs. She can say that there is wrong in the org and we should concentrate in the good and, in a whim, say that is not ok to go to any church even when all churches have something good. The first thing I did was stop questioning her intelligence. Not even think about it. If you do so, eventually you will make it evident and she will be very offended. After all, is not her intelligence speaking, is the cult personality. The cult personality is not intelligent, but she sure is.
They are right about steering her to do something else. Even if it doesn't fill her entire time (although that would be ideal). One of the first things I did (she keeps on telling me "her faith" keeps the bitch in her calmed) was complementing her when she curses. I tell her she sounds sexy when she curses (she actually does so point for me there). Plus, like almost every woman, she has self image issues and so telling her that she is sexy is a big plus. Lets make it clear, I've always thought she is sexy, I am not making this up.
After that, I realized she kept on looking for drink recipes online but she never really tried them. So one Friday I went out and bought a couple of bottles, some ingredients and even got a set of glasses. We've got drunk a couple of times only but we are making it a weekend thing to make drinks, before or after dinner. I have to admit that it was a good idea for both of us. In between this and some pressure at work, drinking has been a pretty good relaxer.
She had also stop going to field service pretty much when I did. However, I do know that she wants to be there. She asked me if my research had shown me that I did not need to preach (since it seems so clear to her that we should do it) and I said I was not sure yet but that the WT teaches that is ok to put your belief on hold while you clear doubts. She has not attended FS since and has not attempted to talk me into going. We've been late to pretty much every meeting and I make sure not to show up around her when she is getting ready (she thinks that as "hurry, we are late").
In other words, and as the books says, attempt to bring out the old personality on her. The pre-cult personality. Take obvious chances but don't be pushy. We have not had a religious discussion for a couple of months now and we are doing great. However, after this last Sunday study I started looking for a chance to ask her what she thought of it. Turns out my 4 year old girls is very outspoken and has already said that she hates going to the hall, that is boring. So last week, after coming back from a long day at work, we laid down in bed. I looked at her and she said "lets get ready". So I repeated what my daughter said (I hate the Jehovah! is so boring!). She smiled and then thanked me for going anyway. Having this nice open moment, I took the chance and asked her. So we had a brief discussion of what I thought were the implications of this new understanding. I did not push anything on her but ended my statement with the questions "Do you not think this new understanding completely destroys the foundation for the authority of the F&DS?" I did not expect or asked for an answer.
I can not wait for this book study to end. It is my understanding that we will be studying the kingdom book next. I can not wait to get to the parts where they explain their organizational structure and the "overlapping generation". I think I am going to have a field day with that one.