. . . I am so very happy to report that today is day number four with the door to Mars' room being left open and giving everyone access to everyone. The first day or two Mars didn't venture out much, but she has spent most of today out and about the rest of the house. She ate wet food alongside the other cats last night, played on the cat house this morning, learned where her food and litter box will be (the one all the cats use), and took a nap with my husband this afternoon.
While there are still bouts of hissing, we feel that tremendous progress has been made!
Once we are all a little more settled, I'll take some pictures for you.
Have a great night!