Well, I have made a bit of progress with Sahara. I have been tying her up after training, just for like 10 to 15 minutes or so and that combined with other methods to work on her being barn sour has made a difference. I feel much safer while riding her and enjoy my experience a lot more because she isn't constantly turning back and even doing "mini rears" to get back to the barn. I think that tying up has helped her learn that the end of the riding doesn't mean dinner time and I will continue to increase the time she spends tyed up so she isn't so impatient.
As far as her learning to not respond to negative pressure, such as standing even though being caught in an electric fence......well, I can't say I see how that is going to happen. She isn't being electrified while standing there. I also tie her in a way that when she pulls on the rope, it will give her some room, like with CA's ring.
Can I just say how excited I am at the progress she has made? Really excited! Thanks everyone for your input. Let's keep this going so it can help more people.