[SPOLIERS] Gone Girl Questions

Just saw Gone Girl, made me think a lot.

Had some questions about motives, that I am still curious about.

SPOILERS!

When she first escapes, does she have a long term goal? Is she gonna permanently be on the run now? [Plan A]

She obviously didn't intend to lose all her money. So calling her old boyfriend was now her plan B. What was her thinking here? To swindle him and vanish yet again? [Plan B]

Did she plan to keep running and only changed plans when her ex was obsessive, or did she plan to use him by killing him and framing him as a way to return to her old life the whole time? [Plan C]

It seemed like she made a decision to go back when watching her husband on tv while eating pudding.

Also, the ending. Staying together for the kid seems a weak as reason for staying with her. I think it's just a convenient excuse to stay so that he doesn't actually have to admit that part of him does actually want to stay, despite/inspite of everything.

Why would she want to stay and have his kid? I think she thinks needs to maintain the perfect facade for the media of happy all american wife as her public image is all she has now, and if that crumbled she would have nothing left.

I am kinda lost. Can anyone explain the motives?