So true. My whole being is practically trained to think in terms of the books. My bad. You're right, though. I can definitely see Blair being all WTF?? at first, then gradually seeing that Nate makes Serena happy.
Plus doesn't Serena technically not have an official "home" at the moment? She's just living in a room in Chuck's hotel. So she could just move (up?) a few floors. Simple.