She stops and you stop with her - her goal is to stop you and not go further so who is winning? and what is she learning?
Granted she is probably very fearful and no you don't want to toss her into greater fear, but she also needs to learn to trust you and get past her fear. A confident leader has a confident pack.
If you stop when she stops then she learns that creating pressure on the collar works and she will do it more. Dogs do what works. We need to teach her that giving to pressure feels good, keeping up with you feels good and her new confident leader would never put her in an unsafe situation.
Think of this - you are a new skier. An instructor has taken you to the top of a hill and you are scared. You stop in your tracks refuse to go further. The instructor comes over to you and you start creating drama about how scared you are. He says 'okay, get back on the chair lift and we won't do this" Did the instructor help you face your fears at all - no. What did you learn? nothing - except that refusing to copperate works with this wimpy instructor. But if that instructor encouraged you to try. He simply asked you to move 1 foot forward on the snow and you succeeded - then you began to face your fears, learned that you could succeed and then actually each foot forward that you went actually started to have fun - you would keep trying and end up totally successful.
So simply face her and gently pull her forward until she gives to you even 1 inch then immediately praise her and create a loose leash. Repeat, repeat, repeat. Within 3-5 tries she should start coming towards you more readily and you can continue your walk.
It would also be really good to have her on the leash in the house attached to an adult. You become a leader and she is a follower. This keeps her from fleeing to her crate and avoiding her wonderful new family. The more time spent together the faster she will learn to trust you.
Love Them & Lead Them,
~Elizabeth & Doug
Dog Training the Way Nature Intended