OK, I am gonna throw a flag on the field! You do not, want to use the "Crate," only when you leave? That "unless the dog has been "Crate Trained," tells the dog that if "I go in here (The Crate?) I'm going to be left alone??" If your going to use a "Crate (at all, in the beginning, it depends on the Dog?" )
In the beginning "Feeding the Dog in the Crate," would be a good idea. If the dog has no "Crate Experience?" You don't want her to feel "abandoned at the start?"
I have never followed the "Da Rulz," exactly myself? And yes ... on occasion sometimes with some dog's ... "There is a Price to be paid, Cough, Cough ... "My first Working line GSD!" But it worked out fine in the long run! Yeah that was a dog, that should have been (uh continued to be Crated ... live and learn.
But here are a couple of links on "Two Week Shutdown."
This first one is the "Real Deal." Just straight up flat out ... that is how it is done. But ... on "Germanshepard.Com," we had someone that was "Highly Opposed," to keeping the dog separated from family in another room?
So there is that. I would prefer to just have the Dog out where I am for a bit time, uh if I did that? But I tend make "adjustments as I go ... so I view "Rulz's, as guidelines?"
And here is another 2 Week shutdown deal.
And generally speaking, Boxer's are not an "Aloof," kinda Dog? I have had "Boxer's and Boxer/Pit's and all of them, just by there "nature luv'd," people. It was nothing I did .... if company came over ... I'd be forgotten for a "Weekend," if they were dog people ... my Stru (White Boxer) slept with them!
I kinda thought every dog was like that? But "note," a Wl GSD, is not .... " That is a Dog that was devoted to me and my wife ... everyone else could just uh ... "Go Away ,,, Now, if you please." Getting him to be "Aloof," with "Strangers, was a mayor accomplishment! And he hated "Toddler's!" But he learned if I was not around ... to "Break Command," if one came near him ... and "Walk Away!" Daddy say's ... "Don't Bite People and Stuff." Another story.
But your girl should be fine, and the "Crate, need not be forever?" My current girl "Bella," was a "Rescue," but I know her history. Her current owner's number three in her first year. Just did not have time for her. She lived in an apartment and was "Crated for 8 to 12 hours a day?
They worked long hours and felt it was not fair to her? So we took her. I did use her "Crate," for about ... Three Day's. And that was because I had "Cat's and she did not live with Cat's. That took me about three day's to "fix." And she slept in her "Crate at night with out issue in the living room."
And the came day "Four," I brought her into the bedroom (with her Crate) and she goes in and goes to sleep. She did fine ... me not so much?? I could not "Sleep," knowing she was in a "Crate??" It was too much for me? So on day "Five," she slept with me and has been there every since (it's been five year's now) and yep she free roams, the house and gets on the furniture at will! She also does not bark like a lunatic or destroy the house.
So yeah ... but you have to do stuff, right in the beginning, to be able to do that. But I tend to think that is most owner's goal? A dog that is easy to live with.