This is a meeting between my boss and myself for the purpose of discussing my job performance. No other attendees.
Have you asked the meeting be done at your home or some location closed to it?
Have you asked if the discussion could be done via skype or some other internet video conference?
Have you asked if it could be done by phone?
What was your employers reply to these alternatives?
(If force to meet at the office, I still stand by my advice that an uber or whatever would be cheaper than fighting them, unless their is some medical reason why that is impossible and you have said so far that it was too long a drive for you.)
I realize it is deeply personal, but what is the nature of your medical issue?