I had to face this with my mom, whom I dearly love but is an incredibly draining houseguest (deals with multiple mental illnesses and a controlling, miserable husband who calls her a zillion times a day and gets her all upset while she's gone)...and she asked me when the due date was so she could schedule TWO WEEK off of work?!?!?
So, I just took the most gentle but firm approach that I could. I told her that we don't really want out of state houseguests for the first two weeks, and that since ALL of our family is out of state, but nobody likes to share their visiting time, that nobody should really stay for longer than a week, or we'll end up with houseguests for a month!
She seemed to take it well...though I'm sure it will 'hit the fan' when she realizes that I will allow other family to visit earlier than two weeks...but I'm sorry, it's the way it has to be. They are helpful and uplifting, she brings stress and stormclouds. I do love her, she's my mom (DH would prefer we just tell her not to come at ALL...but I can't do that.)...but I had to be firm for the sake of my own sanity, my marriage, and everyone's overall happiness during what's supposed to be a peaceful, happy time.
As for the food...don't take offense. Many people show their 'love' that way by giving service...they don't think you can't cook, but why would you want to? I'm Mormon, and believe me, when anything stressful happens, I end up with a week's worth of meals from well-meaning women! It's very kind, and they are just trying to find a way to give you service. As much as I've often thought it's unnecessary, I am learning to be touched and grateful for it...even if the food is the 5th casserole in a row for the week!