I would snap on the leash while she's barking or not....whatever, and then stand by the door, ready to open it, but
DON'T....wait till she's quiet. You can teach her "enough." Be firm, but not harsh. Loud noises sometimes make the dog get even more crazy and they just bark louder. When she does finally stop for a few seconds, tell her, "enough" (when she is quiet, so she learns "enough" means to
stop barking) and then "goooood enough." Don't give the command while she's barking or she'll think the word means
to bark. She doesn't know the word yet, so until she does, don't use it while she's barking. She's going to learn it when you tie it together with the state of being quiet. Later you'll be able to say it to stop her.
Anyhow....then praise her when she complies. If going outside is her goal, then do not let her out until she is quiet. Stand there by the door with your hand on the knob, with the promise of going out but only open it when she is quiet for 2 or 3 seconds. If she starts up, close the door before she gets out. Show her by being super consistant and by showing her a contrast.
Another thing you can do in addition, is to pick up the leash, put on your shoes, act like you're going out for a walk, but don't. Go in and start cleaning your bathroom or something. Do this many times during the day...go through the motions you do when you go for a walk; pick up the leash, put on your coat....whatever, then don't. Do some other things for 10 or 15 minutes. Then see if she will quiet. When she does, reward her with opening the door to go for a walk.
Is she getting plenty of exercise? Sometimes this behavior is just a lot of pent up energy and she can't help herself. Be sure she's getting a good run, fetch game along with obedience practice during her walks. Make her think and walk nicely, sit/stay a few times, etc....tires out her brain too. LOL.
Teach her at other times to pay attention and look at you when you ask. "Watch me." This way when she gets so distracted about other things, you can bring her back to where she needs to be...with you, following you.
It sounds like some leadership straightening out is needed. I'd do a little NILIF with her and make sure she carries out commands that you give her. Be confident and enforce commands, but without sterness, just firmness and lots of reward when she complies. You need to be the one to act... she reacts. It should
not be the other way around. Stop answering to her demands. Ignore them.
Do a search on this forum or ask for help with anything that might help you, like how to teach watch me. It's here somewhere. And other things.