Treat her like a roommate. Right now, in her mind, the marriage is over. So, while she thinks that, she becomes a roommate and things become businesslike. There is no reason to have small talk at this point. She wants her freedom to do as she pleases, then give it to her.
As for making breakfast for her...time to cut that out unless you are fixing for yourself and you have plenty left over. She needs to see what it is going to be like when you aren't readily available to bail her out on bills and responsibilities. It's okay to to wish her a good day, but I wouldn't have any small talk with her.
Sit quietly, the answers will reveal themselves when you least expect them to. The past is gone, the present is a gift and you need to focus on today, allow the future to reveal itself when it is ready.
