No, I haven’t read the book. If you are correct, I’m glad she won’t split away and go third party. That would just mess up any chance of conservatives winning.
Wonder what she is waiting for...
The reasons should be obvious, but the short answer is that it benefits her to step in later, rather than sooner. It's deliberate, strategic planning on her part. She's not "waiting" for anything.
1. She can afford to step in later, where others cannot (due to 100% name recognition and broad, 'broken glass' support).
2. There is zero profit in her stepping in during this (still) early stage, while the field is engaged in something of a dirty demolition derby.
3. By stepping in later, she appears as new, fresh, and unblemished by the prior months' dueling.
4. She gives her opponents more time to suffer from their own self-inflicted wounds, or the wounds of others.
5. She can keep her face and her name in the news virtually for free, avoiding the expenditure of hers and her supporters time, energies, and financial resources.
I could go on, but those are a few of the reasons she's not in yet.