SMA PLT INADVERTENTLY FLEW INTO A TEMPORARY RESTR AIRSPACE DURING A PIPE LINE PATROL. FSS BRIEFED THAT THERE WERE TWO POWER PLANTS NEAR RPTR'S INTENDED RTE OF FLT; BUT THAT COURSE WOULD AVOID THEM. HOWEVER; IT DID NOT. SINCE HE WAS TOO LOW TO MONITOR ATC; CTR COULD NOT WARN HIM.

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WE LEFT ZZZ TO ZZZ1 ARPT TO ZZZ2 ARPT. A BRIEFING BY ZZZ3 FSS INDICATED THAT THERE WERE TWO TFR'S NEARBY. DURING THE BRIEFING; IT APPEARED THAT WE WOULD PASS WELL AWAY FROM BOTH POWER PLANT 1 AND POWER PLANT 2 FACILITIES. THE MAJORITY OF THE FLT TOOK PLACE IN CLASS G AIRSPACE; BUT WHEN WE CHKED IN WITH ZZZ APCH CTL WE WERE TOLD THAT WE HAD ENTERED THE TFR AIRSPACE. ONE CTLR SAID WITHIN 7 NM; ANOTHER SAID WITHIN 6 NM AND ANOTHER SAID 8 NM. WHEN WE CONTACTED APCH WE WERE ALREADY EXITING THE AIRSPACE SO WE CONTINUED. ON THE RETURN TRIP WE RECEIVED RADAR VECTORS TO STAY CLR. THE POWER PLANT 2 IS NOT MARKED ON THE SECTIONAL SO WE WERE UNABLE TO DETERMINE ITS EXACT LOC. THAT ALT THAT WE FLY AT WILL NOT ALLOW RADIO COM UNTIL CLOSE TO A FAC. ATC FACILITIES CANNOT PICK UP A XPONDER AT LOW ALT UNTIL NEARBY. IF WE FLY AT AN ALT WHICH ALLOWS FLT FOLLOWING; WE CANNOT OBSERVE THE DEFECTS FOR WHICH WE ARE LOOKING FOR. THE INACCURACIES OF THE BRIEFING LED ME TO BELIEVE THAT I WOULD BE WELL CLR. THE LACK OF LOC ON THE SECTIONAL CAUSED ME TO IMPROPERLY CALCULATE MY POS. THE LACK OF RADIO COM PREVENTED ATC FROM WARNING ME.