wow. what a post.
i think you stand an excellent chance of matching in a good residency in rad onc. but clinical grades also matter A LOT (as many people have told me before -- preclinical grades don't mean jack). if you get "satisfactory" in all your clinical clerkships, it will hurt your chances quite a bit. so keep up the good work, and don't let your grades slip. I think the particularly important clerkships are (as i was told by my advisor): medicine, rad onc.
your step 1 score is fine, but not stellar. but the rest of your profile is more than enough to make you a strong candidate. for comparison, my step I was 221, and I did not take step II before applications. I matched well.
I think where you go to school also matters in your chances of getting into a top residency, so take this into your considerations. people disagree on how much it matters.
I think rad onc is a must rotation for you. maybe even more than one rotation -- many people do "audition" = away rotations in rad onc, which may be something for you to consider. I think med onc is also a good rotation, and would give you a well-rounded perspective on how cancer is managed. I think your 3 surgical rotations would be 3 hard months that may not be necessary. 1) I'm not sure doing those 3 months would help your application. 2) I'm not sure doing those 3 months help your training THAT MUCH. I wonder what others think about this.
mini-post doc: I'm not an MD-PHD, so input by others may be more useful. My opinion is that your 4 publications and your PhD already speak volumes about your interest and accomplishments in research. No one will doubt that on the admissions committees. If what you want out of the post-doc is more research time, possibly more papers -- great. But if you match elsewhere, you may only have 6 months to finish your project, or have to pass it to someone else. If what you want out of the post-doc is to look better for residency applications, I'm not sure it'll help very much. Again, no one will doubt your research ability or desire. For me, spring semester in 4th year (especially after match) is my last chance for an extended break. Amen for that.
best of luck.