Awww. She looks like a sweetheart. She's reacting quite normally for a cat in a new environment. The fact that she still wants to be petted and is friendly is a good sign.. Put her litterbox food and water in whatever room she's in and she should settle in just fine.
Remember that she just came from a shelter environment where she was confined to a small space (how long was she there btw?). You've just placed her in a HUGE area that's completely foreign to her so it's normal for a cat to bed down somewhere dark and quiet to settle in.
Don't be surprised if when you go to bed you wake up with her up there. If she's very people oriented she will probably be much more social at night when everyone is in bed and it's quiet.