Why get her a new bike? You didn't outline what she's riding today other than an Al road bike. I imagine it's suitable for touring with the right wheel set. Since you're credit card touring, the heavy bits are tools which you can carry. Have her use a frame pack, handlebar bag and/or an inexpensive seat post rack that can hold a trunk bag. Better if it can also clamp to the seat stays. As mentioned above, have her pack light and make sure you both enjoy it first.
My wife is also 5' and I completely agree with @cyccommute that Terry is a good option provided you can find a used one to keep the cost down. We've also embraced the tandem lifestyle though a good tandem (even used) can be a little pricey.