You must cage her because the alternative is far too risky. Try to start with short caged absences. I say "going to the store" if I will be gone 1-3 hours and "going to work" if the absence will be longer. Using key phrases helps them anticipate and judge time. This can decrease anxiety...Key phrases are huge for everything (including household routines).
If you are worried, you can also get a baby monitor that streams video online, or use a laptop to create a live (but private) youtube stream. Send the link to the stream to yourself so that you can pull it up on your phone or on work computer to see how she is doing. You can run it all day in the background and it will also give you an idea of the noise level, as well as any odd/anxious behaviors or injuries.
Do make sure you have a large cage and try to start leaving for short periods of time before leaving for full days.
I would also consider a fallback plan in case the screaming is too much. This is one reason why it can be very risky to keep birds in apartments. In the event that your neighbors complain, make sure you have somewhere you can stay or consider renting a house or a duplex if you have the funds. You don't want to wait and have to scramble in the event that your landlord ends up getting frustrated with the noise.
**Make sure you remove any huts/tents etc (that should happen no matter what for parrots, even if you weren't returning to work, due to hormones) but they can get tangled in them as well. I would consider taking out any frayed rope toys or rope toys in general because they can get toes caught in them and if you aren't home, you can't help.
