RE: I don't mean to scare you off....
Thank you all for so much advice and personal stories. This dog was rescued as an older puppy from people who were going to use it to train pit bulls. They let pit bulls run towards her on a treadmill, getting them all fired up. Ultimately, they would have let a pit bull kill her so it would have an easy kill and be what they call "blooded". The people who rescued her kept her as their family dog, but mostly outside. Then, they set up a huge rescue operation for exotics and put the Rottie in a large cage intended for a medium-sized cat, like a serval or caracal. They can't let her run loose because there are feral dogs around and there are highways.
She doesn't get much attention. Sometimes neighborhood kids walk her. Since I have spent years working with exotic cats, I feel attracted to helping the dog. Let the new volunteers get seduced by the cats. But, since I live in an apartment with a cat, I can't bring her home, except for visits after it's warm enough to leave the cat out all night. I'll bring Rosie home, put the cat out. Take her for a walk, let her sleep inside, go back to the compound in the morning. I give her attention, training, treats, food. It's like a sponsorship. I may bring her home more and more if things go well. I don't really want a Rottie puppy, I don't want to deal with puppies, I was trying to help this individual.