She's telling you at the lope that that is where her draw is. You need to eliminate that first. If you put her on a completely loose rein and don't steer with your legs or reins, where does she go? I suspect it's the arena fence. It doesn't matter why that area is appealing, just that it is. Make that area work for her, trot alongside the fence, turning back into the fence every so often and rest in the middle of the arena. Don't be content with a little jog either, make sure that she is moving out.
Next, don't get ahead of yourself, don't ask for something she doesn't know yet. Forget complicated aids, she has no idea what they are yet and you'll only be getting her more dull to them later on.
Once she can trot around the arena without wanting to go in any one place ask for the lope along the fence, again keeping up with that you taught at the trot, that the fence isn't such a wonderful place to be. From there, don't worry about loping circles, she doesn't steep well enough for that yet.
When you do steer, just pick up and take the slack out of that rein, once she goes that direction leave her alone. Now you should be off the fence and still on a loose rein. If she veers to the left, pick up on your rein rein and steer her way off to the right. If she then veers of to the right go left. Don't worry about her leads when you do this, just steer.
By doing this you will find that she will also get much more straight without any effort from you. She'll start to correct herself and just stay on a straight line. Since you'll be steering softly, you won't be wearing out any cues either.
If at any point she blows you off, bend her to a stop in that direction, making sure that she disengages her hindquarters before you com to a stop then go off again.