There's minimal hissing. Charlie discovered the top floor of the "house" yesterday, I found him asleep behind the towel. Brian said he'd seen him in there earlier eating the little wet food she'd left.
She laid with me on the sofa last night, Brian went to bed, I stayed where I was because I didn't want to bother her. Then, Tommy started yowling out front, he was late, so I got up to feed him. She got up as well, so I just went to bed.
I can hardly wait until I feel secure enough letting her go outside. The breeze is better with all of the doors open, even the screens. Her hearing is what has me most concerned about her being in the out. (And I just shake my head thinking that she had been living in the out before she came to us.)
She does check out the house more, not so much as exploring, but just checking it out. Maybe remembering where the food and water are for emergency situations. Whatever she's doing, she does not seem curious at all.