Can I move my mother from a rehab center in FL to one in KY by car, or does she need to be transported by facility?

She is 86, broke her shoulder, and is no longer able to live alone. She is making slow progress in the Rehab center, but it is 800 miles away. I would like to transfer her to a local Rehab/Nursing facility for the month or so that she will be treated. I paid $100 to have her transported from the hospital to the Rehab center. I hate to think of how much it would cost for 800 miles. The therapist thinks she would be able to make the trip to KY, but I am concerned about checking her out and not being allowed (Medicare) to get her back into Rehab under the 100 day Medicare/Supplemental coverage. She has used about 18 days so far. She will be living with us after she completes therapy.