Your thoughts and tips are most welcomed!!

In order to get ready for Kai, we are moving Eliana into a new room in the house. It just so happens that this room is one of the biggest rooms in the house, as it was created as a "Bonus Room" above the garage. We want to keep our guest room intact as it has its own bathroom, but have no idea how to make such a large room cozy for a little girl. Her big girl furniture arrives tomorrow and we are excited to see how it helps to fill up the room, which is basically empty right now. She seems excited to have a big girl room, but she is also a lot like me and thrives on structure and routine. Yikes!:) Anyways, our plan is to keep her in her current room all this week and just let her get used to the idea of having a room in the big one and see her new furniture in there. This week is also super busy for Jon as he finishes up his current class... 4 major things due the same week!! So we want to move her into her new room maybe next week. Is that too soon? How should we do it? Am I worrying too much? Are you laughing at my first time Mommyness shining through?:) Some of you have seen the room that I am talking about... any suggestions for making it cozy? I would love to hear how my more experienced Mommy friends got their children ready for the arrival of a new sibling! We can totally use any advice that you can give!:)