The key with doing FP is to get as broad an experience during residency as you can. FPs can practice in an urban, suburban or rural setting once graduating. If you go to a strong program, and life throws you a curve ten years down the line, you should be able to segue seamlessly from one type of FP practice to another, as have two friends of mine. One moved from a private rural practice in one state to an urban practice in another. The other hated continuity of care with non-compliant patients and chose to practice three days a week as a director in a major university medical center as an ER doc under the FP umbrella (though I do believe that door may be closing). That's the beauty of FP.
As far as OB goes, many FP docs choose not to do FP for a lot of reasons. So that shouldn't be a deterrent. And FP docs can handle about 85-90% (some say as high as 95%) of what crosses their thresholds without calling in the specialists. Something to think about.
Good luck!
Nu