Ideal career path pre-MBA

Hello all. I will be a rising senior at respectable non target/semi-target for MM in the US this upcoming fall. I'm well aware that I do not have a chance to break into IB out of undergrad, considering that my internship this summer is in FP&A at an F500 Consumer Products company. My gpa after 6 semesters is between a 3.9-4.0 and I scored a 740 on a timed practice GMAT without any preparation or practice. While I will probably need 6+ years of work experience before I have a chance of getting into a T6 MBA program, I've been wondering what the ideal pre-MBA experience would be to become an IB associate after I finish school. For example, I've heard that transaction services at a B4 would be somewhat transferrable, however it wouldn't look as good as something like a finance rotational program on an MBA admission. I know the answer isn't a one size fit all, but am curious to hear you thoughts!