Current PTA here. So the classes that I took that transferred for my BS degree were A&P, microbiology and gen chem and of course your basic courses such as english, psych and math. The only issue you may run into is the dates on those classes expiring depending on when you apply to PA school.I work in SNF rehab and have good exposure to the physiatry (PM&R) PAs but you may still need to shadow to get your hours if needed. If your PTA program is like the one I attended once your in it you may not have time for extra classes since you are in class from approximiate 8:30-5 and maybe longer days during clinicals. I graduate in 2012 with my PT A degree and finished my BS in 2015 if you need an estimate of my timeline.