Yours is a hard question to answer. It really seems to depend on what you are looking for. I attend med school in the southeast and have applied to many programs (both large and small). I have the same step I score and I have found that interviews at least are easy to come by. Because I am doing the couples' match I have applied mostly to university programs, but I have a few unopposed programs as well. The unopposed programs I have gotten interviews to are Bayfront in Tampa, MCE in Birmingham, Ghent and VCU/Riverside in Virginia, and Trident in Charleston which may be at least university-affiliated. As you probably know, applying to a family med residency is largely due to "hmmm...where do I want to live," without knowing a whole lot about the program. Hopefully, the interview/tour/etc. will help to get a feel of the place (whatever that means).
If you are truly only interested in unopposed programs I can only tell you what I have heard thru the grapevine here in GA. Rome, GA is supposed to be a great small program with extensive procedure training. Albany, GA has a good reputation by word of mouth from classmates who have rotated there. Nevertheless, I have not applied to any of these programs. South Carolina also has a good reputation unopposed programs.