I've figured out why she flies up to the fan. It's on her "approved flight path" for getting to me when I'm in the kitchen. She's no longer afraid of the broom I was using to make her fly down. I have to physically nudge her off the fan blade. It's pretty soft on her belly, too, so I'm doing a great job of desensitizing her to the broom, but that wasn't the goal. XD
So, now I'm doing two things: 1) I'm going to put streamers around the fan so she can't fly to it without thinking twice. 2) I'm nudging her off the fan with no fanfare and no attention. At first, the fan landings were mistakes. BUT she realized she was getting immediate attention every time she flew onto the fan blades, so now she does it to get attention. Today, I started nudging her off the blades and immediately going back to what I was doing. If she uses the approved flight path (perches), I immediately acknowledge her and maybe ask if she wants to play, "Rawr! I'm a dinosaur!" Yeah, that's a thing.

She hangs upside down or lies upside down in my hand, attacks a toy and play-growls. I want her to add, "I'm a dinosaur! Rawr!" to the mix.
Right now she's saying, "Pe-e-e-e-e-ek-a-boo!" and it's killing me. XD XD XD So cute. She learned it from my mother.
As for the cage, I think it may be time to make her go inside. I was going to make her spend time in her 20 gallon long first. One way or another she has to learn to be confined. The only issue with the cage is she still isn't a great climber. She'd learn quicker inside the cage...just a thought.
I'm thinking she needs to be fed, well-hydrated and perhaps a little tired before I put her inside for the first time. I'm worried about letting her out while she's fussing and worried she'll fuss for a long time. Maybe I should warn the neighbors they're going to hear some very weird noises?
Input? I'd appreciate it. I think Gabby's death made me feel guilty and now I'm letting Kizzy's cuteness and 1337 human-training skills control me just a bit. OK, maybe more than just a bit.