My character is an 18-year-old tourist from Germany who visits America. While there, she experiences a diving accident and goes to the hospital. The result is a form of quadriplegia from a spinal cord injury. The injury level may be between C5-C7 but I’m not sure which level is more likely. At the same time, I want a level of injury that is significant, but still allows for some independence. This is because she has no money or close contact with her family in Germany. So she might not even have the resources for treatment. In this case, what happens if my character has no choice but to overstay her visa and receive medical care she can’t afford? Additionally, I want her to be able to navigate the world around her in a wheelchair, but still be able to live by herself. The theme I want to drill in with her character is isolation (no family, new country, language barrier, her illness) and independence. So what level of injury and care does she need to execute this theme?
I'll be honest, I don't really know anything about spinal cord injuries. But, you may actually want to reach out to a local hospital, doctor, clinic, surgeon or something along those lines and ask if you speak to someone there and ask them directly about them. Mostly speaking, people are happy to talk about their work and their knowledge, especially if it is something they are passionate about. That's what I would recommend. Catching them during lunch time is often a good way to get information out of doctors, they have quite a grim/dark sense of humor sometimes. xD. Otherwise, you could try a medical-related forum. I'm sure they exist.
Try something like the Canadian Paraplegic Association or another disability related organization. They'd probably have more time to answer your questions than an actual practicing doctor. Who knows, someone may have already asked this question....