While I also grew up in a home where crates were rarely used, a safe, secure room was. Confinement of one sort or another is often most desired.
"LovemyElla" - Obviously it depends on the individual dog, but as a general rule, I wouldn't even attempt short absences until at least 1 year of age. One of our members had a great idea when she first left her dog alone for only 10 minutes. She set up a Camcorder so she could see how her dog reacted while she was gone. I usually just fly by the seat of my pants based on how long I can go in the house without having an eye on the pup/dog at all times.
I really think it's one of those things that you can judge by the way the dog behaves. Since you have the ability to work from home for 2 days/week, you have the advantage of seeing how your puppy spends its entire day. You know how long the puppy likes to go before going out, as well as eating, or when boredom sets in. I think by the time your puppy is a dog, you will see that she sleeps for the better part of the day, and really only seeks your attention because you are there. That will be your cue to start off with very brief periods of time.
Always remove any temptations, such as garbarge, food, shoes or any other hazard (including her own toys on which she could choke). Some dogs can NEVER be left with free range. My neighbour has a very well behaved 13 year old Chocolate Lab, Kimmie, who has been "fixed" since she was a youngster. However, if she is "cross" with her "Daddy", she will rip up carpeting, or drywall and eat it. She had to have emergency surgery last summer, and nearly died! I also had a Lab that could never be fully trusted either, so if I had to be out for any length of time, she went in the Laundry Room, which is also where she slept at night, with her sister, my Golden.
I'm sure that's the longest "non" answer you've ever read, but I hope you grasp my point. I also don't wish to paint all "Labs" with the same brush.
It just so happened that those were two examples with which I'm very familiar. Jack Russell Terriers are an entirely different story. My answer for them would probably be NEVER.
As with human children, most rules have to be "played by ear". Good luck to you, and don't stress the confinement. Many dogs feel very safe in their "dens".