I wrote my last post quickly because I had to leave. I have one more thing to add. With DS it seemed that he went from "not ready to go home" to "ready to go home" almost without any warning. He just "got it" one day. So you may not see the gradual progress you're expecting; your DD may just surprise you.
(Then again, I maintain to this day that they sent home DS because they had a set of twins and a set of triplets already, and another set of triplets was born the day they discharged DS. So maybe they just ran out of room. )
The NICU is a scary place, no matter what. You just take it one day at a time and celebrate small victories. If your DD needs a tube right now, then that's how she'll get her nutrition for now. It won't be that way forever. But it is so hard to have to see our little ones in the NICU instead of home with us.