Hi, welcome to the forum!
Well, at least you know the source of the problem- lack of respect for you and others that handle the mare. This is good! So many people have these issues and are determined to prove that it's something other than a respect of space..
So how do you solve it? Become more clear, concise and firm with what you ask of her. Is she trying to drag you along as you lead her down the aisle? Then turn around and back her booty up a good length. Do a ton of groundwork, really focus the groundwork on making sure that no matter which way you move her feet, she moves them away from you and not into you.
For example: Some people have the issue of a shoulder pushy horse when they focus on moving the haunches away from them- but what they don't realize is that the forehand engages toward them, if they are asking for the haunch turn incorrectly, and now you have a horse that thinks it is okay to turn their shoulders into your space.
All in all I think it would be beneficial for you to have a trainer that can show you all these things in person, it's very hard to describe in writing.
As for the spookiness, your horse is trying to give you a reason to back off her. I see it all the time. If you know she will spook at the gate, bend her, make her do some lateral work or something that she will have to put her mind to so that she can't focus on the spook. By keeping her mind engaged during the whole ride she won't have a moment to think about the silly spook.
We are not human beings having a spiritual experience. We are spiritual beings having a human experience. -Pierre Teilhard de Chardin