All Kerry-McCain counties are Kerry-Romney counties. It would be more interesting to list Kerry-Obama-Romney counties.
I'm using the numbers posted here. I don't know if they've all been updated. Most are very close and could change if Atlas numbers aren't final. Anyhow:
Volusia, FL
Calhoun, IL
Madison, IL
Menifee, KY*
Rowan, KY
Wolfe, KY*
Arenac, MI
Big Stone, MN*
Ste Genevieve, MO
Belmont, OH
Jefferson, OH
Monroe, OH
Stark, OH
Houston, TN*
Jackson, TN*
Kenedy, TX
Boone, WV
Braxton, WV
Marion, WV
McDowell, WV
Webster, WV
Iron, WI
Pierce, WI
* denotes McGovern county
