C208 PLT FLIES THE WRONG RADIAL ON APCH TO TWF. ATC SAVES THE DAY.

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FLT PLAN SLC TO TWF. ENRTE ON V4; I WAS GIVEN INSTRUCTIONS TO CROSS BYI VOR AND PROCEED WITH THE BYI TRANSITION TO INTERCEPT THE TWF LOC. AFTER XING THE BYI VOR; I MADE A L TURN TO FLY OUTBOUND ON THE 230 DEG RADIAL. WHICH IN FACT I TURNED ALL THE WAY AROUND TO 060 DEGS AND PROCEEDED TO WHAT I BELIEVED WAS THE 230 DEG RADIAL. I FLEW THIS FOR THE EXTENT IN WHICH THE BURLEY TRANSITION STATES AND WHEN I WENT TO SWITCH TO THE LOC IT WAS NOT THERE. INITIALLY; IN THE FIRST L TURN; I MADE MYSELF DISORIENTED; AND DID NOT REALIZE MY MISTAKE UNTIL TWF APCH CORRECTED MY ACTION. I ATTRIBUTE PART OF MY MISTAKE TO WORK OVERLOAD; AND THE OTHER NOT PAYING ATTN TO MY SITUATIONAL AWARENESS. FROM DAY ONE FLYING WITH THIS COMPANY; I HAVE FLOWN ACFT WITH IFR GPS; AND THIS ACFT DID NOT HAVE ONE. MY WORK OVERLOAD CAME FROM BEING TOLD TO MAKE AN ARC TO INTERCEPT A NEW VICTOR AIRWAY; GIVEN 2 HOLDING CLRNCS; REQUIRED TO GIVE MULTIPLE ALT CALLOUTS; RECEIVED A LARGE CLRNC FOR THE APCH; ALL WHILE FLYING SINGLE PLT IFR. THE SOLUTION TO THIS PROB HAS BEEN DEALT WITH BY MY COMPANY AND I HAVE GONE THROUGH SOME RETRAINING.