I don't see why you would need two years to cover what is essentially three semesters of calculus. In my day, the two courses were sequential with Calculus AB taking one semester whereas Calculus BC took two semesters. In my kids' district today, Calculus AB is a required prerequisite for Calculus BC and the courses takes two semesters each. Calculus AB preps your for the AP Calculus AB exam while Calculus BC preps you to take the AP Calculus BC exam. Even if Calculus AB were not a required prerequisite for Calculus BC, it may be difficult to jump right to multi-variable calculus without any prior background. Calculus BC covers vector valued functions, partial derivatives, directional derivatives, multiple integrals, line & surface integrals and Green's & Stokes' Theorems.
I did see in our science sequence that there is actually AP Physics A, AP Physics B and AP Physics C and that you don't take all three. Our district also requires World History before American History and frankly I think that is a better approach.
