It sounds like she is lacking confidence when she gets away from her familiar surroundings. I think that it would be a good thing to take her out daily, even if it is only hand walking her to let her get used to things. Before you go out with her, see how well she responds to you on the ground in the area she is most comfortable in, like the paddock or the roundpen. You didn't say if you have done any work with her on the ground yet. If not, it would be a good idea to see how well she responds to you on the ground before heading out. She should move away from you when you ask her to, you could try moving the hindend away, the forehand away, she should back up when you want her to and walk on, turn and stop when asked. When she can do these types of things by responding as soon as you ask her to with the least amount of pressure this is great. She needs to respect your space before you try heading out for walks with you. Once you feel that she is ready, you could try taking her out of her comfort zone, don't expect to go very far at first, be happy if you can go for only a little bit with her listening to you and respecting your space and then head back before she starts to lose her confidence. You will need to keep repeating this, hopefully getting a little further each time before she loses her confidence. If she starts to lose it and get crazy on the walk, practice what you worked on on the ground, making sure she respects your space, work at this until she is listening to you and calm or at least as calm as she can get.
Most important thing is for you to be able to stay confident as well, if you don't feel comfortable she will pick up on it and it will not help her out any. So if she loses it remember to stay calm and breathe, remind her to respect your space by moving her away from you and getting her to focus on you.
Just remember if you get out there and she loses it before you get back to her safe place stop and get her attention and her respecting your space and hopefully calm before heading back to her safe place. You really don't want her to learn that she can start to act that way and then she gets to go home. That is why it is important to start with very short walks at first.
I hope this helps out a little, I'm not the best at explaining things. Maybe someone else here will have something better to share.