training a rescue dog

Question
I have recently rescued a dog from a puppy mill. She is a great dog, but has issues with being comfortable around people. When we first got her, she would be scared if we dropped a pen on the floor, she would flip out and run. We used to let her out in the backyard with our other dog, (not rescue), and she would play with him. Once we open the door to let her in, she would run away and if we walked towards her, she would run away as well. Now, it has been 2-3 months but she is still some what the same. She is a little better with coming in the door, but runs in and to her "corner", which is the mudroom where her crate is. She seems to be most comfortable and safe in her crate. We don't lock her in there incase she wants to come out, with never happens. My main question is: I need help training her so we can play with her, and so that she will become more comfortable and not scared around other people. Sometimes i think i only have one dog because i never see her unless i go into the mudroom and pet her. The weird thing is, when i take my two dogs on a walk, she is a normal dog; she wags her tail, she runs, and looks happy. Once she gets in the house and sees people, she is scared. I need help training her so that she can become more playful and comfortable around people. As of right now, she doesn't come 2 feet away from her crate, she never moves at all. Please help me, fast! Thank you so much for taking your time to read this.

Answer
Well the best way to do anything with a dog like this is go slowly-even if when you are walking her she goes up to people,have a friend approach her on a walk and talk to her,and have that friend give her a treat

Also have that friend come to your house and to really talk to your dog,and when she get comfortable with that one person(over a period of days)do the same thing with a couple of other people

It may also help to look around for trainers that can come to your house and can deal with a skittish dog-as that is the best way to train a dog like her,and a trainer can show you the best ways to make her become more social,obedience school would be too much right now for her,it would be a lot better for a trainer to come to her