There have been some very interesting suggestions. Here's another. If at all possible, get her on a very predictable schedule. Having a very regimented schedule, and by that I mean doing everything the same way every time. That will allow her to relax as cues for what is coming next never varies. It sounds likes there is very little time that she is in a relaxed state. Over time, when everything is the same, every time, and there are no surprises, she will begin to relax and trust her surroundings. Then you can gradually add new stimuli.
Use a crate when it isn't convenient to have her in close proximity. It will give her a chance to take a deep breath and relax. I think tethering her to you is just too intense for her. She needs to feel she has a certain amount of free will.
