Leaving baby for 4 days...pumping help!

Looking for some tips. I'll be going out of town without baby for 4 days, 3 nights when my daughter is 11 weeks old. She is EBF now and I have 72 ounces in the freezer so far for when I'm gone. I have 2 questions: how many ounces should I have stored to make sure she has enough for when I'm gone? And how often do I need to pump when I'm gone? What's the least that I can pump? If you have any other thoughts/advice I would love to hear it. Thanks!