Spyralle:
I haven't read the rest of this thread, only your initial post, so please pardon me if I'm repeating a lot of what other people have said.
My mother and I had exactly this argument for years. It was very difficult. I knew that she would never get along with my husband, and that the stress of having her in my home, day in and day out, would drive me over the edge. I offered again and again to help her find an apartment, but she always turned me down.
After a great deal of thought (and therapy, too), I came to the conclusion that while I had a responsibility to make sure that my mother was OK--in terms of money, medical care, etc.--I did not have a responsibility to make sure that she was happy. Her happiness was her own problem, just as everyone's is. And though she saw it differently, I knew that I had to stick by that conclusion, because it was right.
When it looked like she could recover from her brain injury, I did decide that she should come and live with us. She could not live by herself, even in an apartment, and I wanted her to have the security of living with her family. I deeply regret that I never got to do that; her condition deteriorated and she died last June. But I know that I made the decision to take her in out of love and from a place of freedom, not out of her having strong-armed me into it. All the difference in the world.
You are NOT a "crap daughter." Your mother is trying to give you a burden that is not yours to carry. Whether she ever realizes it or not--and of course the odds are against it--you have a duty to yourself to realize it and live it. She cannot take your freedom from you in the name of her own security. Life doesn't work that way.
You're willing to have her nearby, which wouldn't be easy, I imagine. That's a lot. The fact that she can't see that and choose to be happy is her problem, not yours. Please, please keep reminding yourself of that. You have offered to make room in your life for her. If the opening isn't exactly wide enough to suit her, she has only herself to blame.
Again, please forgive what is probably a very repetitive post. Time doesn't allow me to read through the thread right now, but I wanted to reply to your initial post. I've been there, and it's not easy. You're a very good daughter, Spyralle, and I hope you will allow yourself to feel that.
All my best,
daylily