What a difficult situation - I'm so sorry you are going through this.
I can't believe that a vet would watch an animal suffer, struggling for breath, and refuse you. It really seems like malpractice, and it seems unnecessarily emotionally wrenching for you. Have you asked about palliative care and pain reduction? Did the vet out and out say no to euthanasia, or are you afraid to ask?
I'm not sure the blindness is a compelling issue by itself, although it certainly makes things more difficult. Sounds like he trachea problem is #1, followed by her joints. Refusing the surgery is an act of kindnesss on your part.
Is there a veterinary hospital you can call for advice? I wonder if there is a "doctor on demand" sort of service for pets. Maybe seeing a video of the dog struggling and having you fax the current vet records would be enough to let them prescribe something? If not, I would consider some way to make the trip - perhaps with anti-anxiety meds for the dog or whatever is needed to get her to your destination. She's suffering no matter what you do.