I'm in the same boat as you, and i plan on taking the MCAT next spring.
I bought some books and have allready started studying. Mostly the verbal, because we obviously don't know organic or physics yet! The books make alot of the formulas very easy to remember, so I think it will help with taking the actual class. I'm also taking TPR in November.
If you want to take it, my best advice it to be prepared and get more input from fellow SDN'ers.
i know of several people from my school who did that. while it was really rough on them because they were taking two really hard sciences while trying to study for the mcat, they had the benefit of at least having the information fresh in their heads when they took the exam. so really it's just a matter of figuring out how much time you are going to have and whether or not you want to have a life this year. good luck and don't stress out to the point of insanity like i did!!!
On one end, I could see the difficulty of taking those two classes at the same time. But, in my case, I took the MCAT a full three years after taking those classes, and while I still got a 35, it took a LOT of making up for lost knowledge. If you're taking physics while studying for it, the hardest part of the physical sciences for many would be in stride, so I would say if you feel like you can handle it go for it.