I am a post-bacc, too!
I don't think they expect us to come up with the whole "treatment plan" since we cover little standardized tests in the undergraduate-level courses. What I did is trying to recall what I observed in the school clinic and hospital, focusing on what I know more and putting less emphasis on the standardized tests. For example, for patient with TBI, I would probably start with taking a look at his medical chart and/or his schedule with PTs or OTs...,things like that!
That's just my thoughts, but of course, research will definitely help!!
Good luck! You'll do a great job!!