I think she will just choose the Barney house to move into. You could move some of her nest over. Don't worry about the change from the penthouse as she'll have accepted the new cage if she has a bit of time in it before moving her over. Personally I wouldn't take the Penthouse away now (sorry Shannon!) - just my view - if you're planning to move her soon anyway. She will see the new cage set up is different and just head for the best nesting place (probably the Barney house). If it has some of her old nest inside it will smell familiar
Some things are bound to be different, but it's the scents that help and also having time to be in the cage before moving. But as Shannon says, they have different personalities.
Incidentally do you know about plastikote?