PLT OF A C182RG FAILED TO MAINTAIN THE ASSIGNED HDG AND ALT WHEN BEING VECTORED TO JOIN THE LOC COURSE. IN ADDITION; THE PLT EXPERIENCED AN ERRONEOUS INDICATION FROM #1 NAVAID WHICH COULD HAVE BEEN CAUSED BY THE UNUSABLE AREAS INDICATED IN THE ARPT FACILITY DIRECTORY.

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DURING THE ILS RWY 23 APCH AT TRI; APCH CTL GAVE THE INSTRUCTION TO TURN TO A SPECIFIED HDG TO 'JOIN THE LOC.' I WAS VERY BUSY IN THE COCKPIT CONFIGURING THE NAV EQUIP FOR THE APCH AND INTERPRETED THE ATC INSTRUCTION AS A SUGGESTED HDG AND CLRNC TO JOIN THE LOC. AFTER XING THE LOC COURSE; I BEGAN A DSCNT TO THE NEXT MDA. I ALSO FLEW THROUGH THE COURSE AND DURING THE DSCNT; I ATTEMPTED TO REJOIN THE LOC. SIMULTANEOUSLY; 1 OF THE 2 LOC INOP FLAGS DISPLAYED ITSELF ALONG WITH A FULL SCALE NEEDLE DEFLECTION. THE SECOND LOC NEEDLE INDICATED 3 DOTS OF DEFLECTION WITH A MOMENTARY NEEDLE OSCILLATION AND INOP FLAG. I BELIEVED THE #1 NAV TO BE INOP AND CONTINUED THE APCH WITH THE #2 NAV INST. HAVING CONTINUED THE DSCNT DOWN TO 5200 FT MSL; APPROX 800 FT BELOW THE LAST ASSIGNED ALT AND NEARLY 60 DEGS FROM THE LAST ASSIGNED HDG; THE CTLR ACKNOWLEDGED THAT I WAS OFF COURSE AND DSNDING TOWARDS RISING TERRAIN. FOLLOWING THIS ACKNOWLEDGEMENT WAS AN INSTRUCTION TO CLB TO 6000 FT MSL AND TO FLY A NEW ASSIGNED HDG TO JOIN THE LOC. I COMPLIED WITH THE NEW INSTRUCTIONS; THOUGH I HAD BECOME CONFUSED AND SLIGHTLY DISORIENTED WITH REGARD TO MY POS. AFTER REGAINING ORIENTATION AND CONTINUED VECTORING I WAS ABLE TO SUCCESSFULLY REJOIN THE LOC AND INTERCEPT THE GS TO SUCCESSFULLY COMPLETE THE ILS APCH. IN SUMMARY; THE CHAIN OF EVENTS OCCURRED AS FOLLOWS: 1) CONFUSING THE INSTRUCTION OF THE CTLR TO FLY A VECTORED HDG TO JOIN THE LOC WITH AN ACTUAL CLRNC TO BEGIN THE APCH. 2) PREOCCUPATION WITH CONFUSING INST INDICATIONS. 3) LOSS OF ORIENTATION. CORRECTIVE ACTIONS: 1) COMPLIED WITH NEW ATC INSTRUCTIONS. 2) REGAINED ORIENTATION WITH RESPECT TO THE LOC COURSE.