The final verdict is here - Bella will not be my riding horse. I had a long talk with the vet today and was basically told to just cut my losses. Which is nothing surprising, I was told that by another vet a long time ago. But I had to hope, and try.
I am going to look at horses if I can make all the little things work (just feeding critters here is pretty complicated). Not taking the trailer this time. Going to have to raise some funds before I can do that.
Right now though, I'm going to get some sleep.