How long has it been since you adopted her?
How big is she? I ask because Ruffwear has a leash called the Quick Release. It's basically a leash built into the collar for quick, easy access. There are other brands that are similar, but I'm more familiar with this product. As long as she is tall enough and you can get to her neck, she'd already be leashed, that you wouldn't have to go through all the leashing drama. Leaving a trailing leash on her is another idea, or keeping her tied to your waist is still another.
Back to your original question, is ignoring unwanted behaviors the key, I'd say in your case, yes. It's not something that will produce results overnight, but at the risk of inadvertently reinforcing behaviors you don't want, withdraw all attention. Consider this too, negative attention is still attention. Since she's had no training for 5 years!, you can't correct or punish behaviors that the dog doesn't know, unless you do so with instruction. Of course I always believe that's the case with dogs. But I'm with you, you'll need to go back to basics teaching behaviors like sit, down, stay, wait, off, leave it, ect.
Dr. Ian Dunbar has a good series of training videos. You may even find them at your local library. Or go to dogwise.com to find them. You may also find some free and useful videos here:
(Bookmark This Site - Training Videos)Bookmark This Site - Training Videos - Dog Training Forum - Dog Forums - all breed dog forum.