Unless you have lots of free time, it won't matter. From what I gathered on TY interviews, they were more interested in why you picked your future career rather than why you want to be a TY. They just want nice people who work hard and don't complain.
That being said, I didn't do a TY, because of the tailspin of not matching. I ended up doing a prelim. Not sure if it was better or worse, but I felt like a I had a pretty good handle of internal medicine at the end; there was about 10 minutes where I considered finishing the residency b/c I did find some of it fascinating. In these opening two weeks of residency, I'm not sure that it helped one bit. I can manage the heck out of an ESLD patient, but I don't think many of them come to my clinic, now. I wish I'd done an extra med-onc clinic month, and maybe ENT or thoracic surgery for a month. Maybe skipping noon-conference and going to tumor boards would have been helpful, as well.
There just isn't much overlap between rad-onc and 'real medicine'. As far as history taking goes, you kind of use the chart/EMR mostly, with the patient there to clarify to help you stage properly. Learning a good physical exam is pretty important, but mostly for delineating anatomy and palpating nodes. I picked up my first mitral stenosis murmur 2 days ago, and nobody cared except me. Assessment of general medical condition to figure out whether a patient will be a good candidate for multi-modality therapy becomes more geshtalt rather than anything you learn in internship. Maybe a radiology month where you actually learn something would be helpful, but most of those electives end up being vacation.
In the end, I'd suggest the easiest program in a city you like to live in. Unless for intellectual curiosity's sake you want to learn medicine/surgery or whatever.
-Simul
