<p>I can’t advise on what calculator is needed for multivar, though I can tell you calculators aren’t allowed on exams for Calc II. In re deciding whether or not to take Cornell’s calc classes, I would say it depends on your major and how much you will truly need calculus for your career plans. I decided to keep up with calc so it would help with economics in the future, even though my good score on AP AB Calc fulfilled my ILR math requirement. I had a pretty rough time in going from AB Calc to Calc II at Cornell (Math 112), and eventually dropped the course after my advisor and others let me know it wasn’t all that necessary for the social sciences (and I got the results of my disastrous first Prelim, haha). For economics and public policy, my understanding of differential calculus from high school was perfectly sufficient. </p>
<p>As someone who’s definitely not a natural at math, I would start with Calc I (Math 111) if I absolutely needed calculus on my transcript. Though doing so would mean that forfeiting my AP credit, I would be gaining a MUCH better understanding of the topics covered in Calc II. There’s quite a lot in Calc II that you don’t learn in AB Calc, and if you’re not a natural, it’s damn near impossible to figure it out on your own. I spend many long nights and office hours trying to work through problems to literally no success. Though I’m willing to guess you’re much better than me 
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<p>[Cornell</a> Math - First Steps in Mathematics](<a href=“http://www.math.cornell.edu/Courses/FSM/index.html]Cornell”>http://www.math.cornell.edu/Courses/FSM/index.html) may give you some good ideas. I also recommend consulting older students in your major. I’m sure there are even some on this message board who would be happy to help.</p>