Scratching at the windows and doors makes me wonder if she was allowed to go outside in her previous home(s). When she does that, can you dissuade her from the window or door with a treat or a toy? I am thinking this would be a good chance to make her an indoor-only kitty.

Cassie stayed under my love seat for a few days after I first brought her home. She allowed me to reach under the love seat to pet her. I know she was coming out at night to eat and use the litter pan because the food I put out for her was gone and the pan was used. I hope your kitty gets braver! What is her name? Come on out, kitty