Every few years, Columbs AFB (KCBM) has a civilian fly-in where we spend all day in safety seminars and getting tours of the TRACON and get to fly the cool Texan, T38, and T1 simulators there. I try to attend if at all possible, so I've managed to log a landing there. They did require PPR filed at least 10 days in advance (they supposedly did background checks on the requesting PIC) and all aircraft had to be on a flight plan, either VFR or IFR, coming and going.
I've never been brave enough to request an approach to the runways at KCBM with their TRACON. In fact, they will nearly always start giving you vectors away from their Charlie is you as much as point your propeller at them.