You know we are all here for you. I have not had to go through this with a dog, personally. But I have with my cat, just recently. And my mom and sister have had elderly dogs.
After the vet check you might want to look into a form of a diaper for her while you are not home. My sister used old undies for one of her dogs when she was in heat. It was funny to see, but it worked.
They do get old (unfortunately). But she sounds like she is still full of life other than the slowing down and bladder control. You will have to adjust things accordingly for her as she progresses. Like her not getting on the bed. She could hurt herself getting off (or falling off) once she's up on the bed.
It will be rough on you, but I know you'll do what ever you need to do for Casey. She's such a beautiful girl!