LOL. Dude, there is NO way she will get a new GC before traveling. Have you looked at the processing times? Up to FOUR YEARS.
what she will get is a 46- month extension letter, which she can use for travel along with the expired GC.
It really is not advisable to use an address other than where you live. USCIS has been known to make unexpected home visits, to verify relationships. I would guess you’d want them to show up where you live together, since that relationship is the entire basis for removing conditions.