I'm remembering how exhausted my wife was feeling after each of our babies were born. (I was tired, too, but nothing like my wife.) I'm also remembering how she and I wanted to spend time together with our babies.
I'm thinking you will want to spend time with your husband and new baby then. Your friend will be in the way. From the way she has behaved in the past, I predict she will expect you to entertain her when she arrives and she will pout when you are too exhausted to do this. Why put yourself and your husband through that? Frankly, in my opinion, your husband and your baby should be more important in your life at that time than your friend.
I suggest that you tell her that you are very sorry, but that your baby and your husband and you will need time together, just the three of you, for ___ months after the baby arrives. Tell her that you will not be having any house guests during that time. This is not unreasonable of you. If she pitches a fit, then maybe she is not much of a friend after all.