You know, The "umbilical" leash thing is not so bad.. You do not do it all day long, Just during certain times of the day, Your dog obviously is not ready for complete freedom yet. You can keep her in a gated area when you are not able to keep an eye on her, And the leash in the house is just a way to train her when you have the time to take her with you when you are in different rooms of the house... You could always give her a Bully stick while she is on it to keep her busy.. A lot of people on here get those for their dogs, and apparently Dogs love them.. Anything that will keep her mind off of your Shoes, and other stuff. Praise her while she is chewing on it, and give her the Firm "No" when she chews on the stuff you want her to stay away from. Replace the shoe she is chewing on, and replace it with what she is allowed to chew on, and then praise her like crazy.
The leash is only so you can have Sierra with you when you are cooking dinner, or just sitting down hanging out.. Praise her for her behavior when she is laying beside you being a good girl, and she will soon learn what makes you happy,But keeping her in one area of the house because she is chewing everything up is not going to teach her how not to do it... You will need to show her.
I wish Teenage girls could train as easily as Teenage Pups do.
(Big Smile)