Hi Cat Person, thanks for your suggestions! Your ideas don't sound cruel at all, sometimes a cat does need to be kept in a more restricted space, it all depends on what's right in each individual case.
I know she was in a smaller cage at the hospital, (for five days) but vet said the size of Queen Eva's Castle is okay. (I brought pictures in to show vet the set up)
Queen Eva has been eating with hearty appetite for three days now while still in the hospital, there wasn't any need to withhold food or water. The mess did not upset me, she was just being her havvok rekkin self, and I fixed it now so she can't repeat it.
Queen Eva is used to being crated. She lived in her Castle for her first week here, and has continued to use it during outside adventures, with no problems.
(I take my cats out, harnessed, in a fenced yard. Queen Eva has been kept in her Castle when we are in the yard, almost exclusively, except for two short experimental forays for just a few minutes at the end of our last two outside sessions. Since then winter has come, so no more outside for them)
She was just going a little bonkers what with being newly home and all. And yeah, I freaked out.

But it's better now, whew!
She's had her pain meds, another meal (hand fed

), a good long cuddle with me and now she's napping again.
I've decided to keep her Castle out in the living area. It's warmer out here and she can see me and the other cats, and she can see into the bedroom, so when I go to bed, she will know where I am. I have fleece blankies draped on the sides of the crate, and the back faces the wall.
I appreciate you taking the time to post your thoughts. Many people read these boards and your helpful suggestions may be just what someone else, with slightly different circumstances, needs to know.

.