Personally, I would recommend taking 2OA3 for sure in the summer. It was really difficult during the year, even with Dr. Stover teaching it. I actually found 2OB3 more straightforward (pretty much memorizing reagents, reactants, and products), but definitely sign up for a tutor using the list of tutors they provide on avenue. I took Physics 1B03 during the summer, and it was really easy (I could have def gotten a 12 if I had been more focused, but still got a 10 without studying a lot). But I took physics here at Mac. I don't know how it is at York, but I'm assuming that it'll still be pretty easy. Honestly, if you think you're up for it, take both in the summer. And it doesn't even have to be all in one summer. If you can, take one this summer (I'd do 2OA3) and leave the other for next summer (1B03) - so you don't burn yourself out. That's exactly what I wish i had done.