I do trips like A,B,C,A all the time in a car. Sometimes even A,B,C,D,E,F,G,H,I,J,K,L,M,N,O,P,Q,R,S,T,U,V,W,X,Y,Z,A trips in a car.

If you're sprinkling in little rules like "ah but you couldn't park at C", well, "the bus doesn't go to C" is also a valid restriction I run into often. So often when I take transit, its drive to train station -> take train someplace -> take bus someplace -> walk several blocks to destination -> walk several blocks back to bus stop -> ride bus to train station -> ride train back to train stop -> take car home so a A,B,C,D,C,B,A trip is actually quite common just to do the same as A,D,A with a car.