What a wonderful ending to your adventure, or maybe I should say beginning because as we know life with a new dog is never dull.
The separation anxiety seems to be a common thread with many of the stray/shelter dogs. I have one myself. First of all, time does really help heal. The thing that settled Tucker down when I left was leaving him with my other dog. Initially I kept them separated with Tucker in the kitchen and Hannah had the rest of the house. Tucker was a basket case. After he had been around enough for the two to become used to one another, I put Hannah in the kitchen with him and soon thereafter gave them both the run of the house. Once I did that, he could tolerate being left. Initially he didn't want to go outside without Hannah, but eventually (and this took quite a while) he was able to go by himself. Initially in the house Tucker stuck to me like glue, but as the days turned into weeks, he came into his own and started spending more time with Hannah instead of me.

Just give Maddie lots of love. What she has been through was traumatic for her. The more sure she is that you will be there for her, the more comfortable she will be on her own.