[Disclaimer: Personal Opinion from current applicant]
You've probably read a lot of posts about similar topics (i.e., where to do aways), but the best advice I received is to do rotations at programs you want to go to for residency. Beyond that, doing an away at a school may not "open up" another region of the country, it will improve your chances of interviewing at that specific program, but provides no guarantee for any other interviews there.
From personal experience, I did three away rotations in the northeast and got many interviews here and scattered interviews in other regions (mid-west, mid-atlantic, west coast). Other applicants in my class did west coast aways and only got interviews at that program. It seems to me that schools with a national reputation will interview all strong applicants, regardless of region, while state schools and community programs are more likely to take applicants they think will rank them highly and interview more regionally. However, if you're in the Northeast and want to be out West or down South, I think it would be wise to do multiple aways in those areas.
There are always three speeches, for every one you actually gave. The one you practiced, the one you gave, and the one you wish you gave.