Regional bias + advice
Is there a big regional bias in urology? Along those lines, what would you think would be the wiser choice of the two -- accepted for away rotation at the regional school which happens to be the dream school and presumptive #1 program versus an away at a very far away program that is in the upper echelon of urology programs nationwide (but not necessarily one that I'd want to attend)? If you could only do one, which would you think? Good applicant, but nothing amazing that really stands out aside from maybe better than average research, an average step1, and a good GPA.


Sounds like you answered your own question. You need to go with the obvious: your regional program.
Here are the reasons:
1) It is your #1 pick.
2) You're from the area.
3) You want to stay in the area.
4) You don't want to attend the upper echelon program.
5) The upper echelon program will probably wonder why the hell you're out of your comfort zone and going far away to do a rotation when you don't even want to be there. Maybe you're just there to get a letter from a top tier chair or professor? They'll sniff that out pretty quickly when your heart is not at work.
6) You don't want to waste a month at a program that you don't want to be at in the first place.
7) You're an average applicant. Even if you rotate at a top tier program, what makes you think you'll match there? There will be a bunch of much better candidates/rotaters that will be there as well. Top notch programs look for top notch applicants, not average joes like yourself (this is based on your own description above)
8) If you get into a Urology residency program, you will be trained to be a Urologist regardless of whether the program is the #1 program in the USA or the last.
Bottom line: go with your top choice. Go with what feels right. Don't go for a program that you probably don't have a chance at.