Answers:

7: Mill Valley AFS, CA; Vandenberg AFB, CA; and Mount Santa Rosa, Guam.

Also, at Gibbsboro AFS, NJ, the ARSR-4 radar equipment (as well as the FAA work center and office) is located in the old AN/FPS-27 search radar tower, while the radar itself is in the ARSR-4 tower immediately next to it.