1995 FORD F-350 SD Electrical System Problems

I HAVE OWNED MY F350 DIESEL FOR 11 YEARS SINCE NEW, IT HAS 127,000 MILES ON IT, WE USE IT FOR WORK, HAULING, COMMUTING, AND TOWING 12,000 LB RV ON VACATIONS. IF WE DO NOT GET OIL CHANGES, WE CANNOT START OR DRIVE OUR VEHICLE, SO WE TRY TO KEEP UP WITH REGULAR MAINTENANCE, WE HAVE KEPT PRETTY MUCH FACTORY EVERYTHING EXCEPT REAR AIR BAGS. PROBLEMS WE'VE HAD INCLUDE REPLACING MASTER CYLINDER, VACUUM PUMP FOR BRAKES, BUT BRAKE PADS AND CALIPERS NORMAL WEAR AND TEAR. VERY TOUGH TO REPLACE REAR DRUM BRAKES. GLOW PLUGS REPLACED AT LEAST 4 TIMES, RELAY SWITCH REPLACED MORE THAN 5 TIMES EARLY ON, STEERING COLUMN COMPONENTS LOOSE AND FIXED 3 TIMES DUE TO LACK OF UPPER DOOR HANDLE TO HELP PULL YOURSELF INTO CAB. WE HAVE HAD A DIESEL LEAK FOR A COUPLE YEARS UNDER CENTER FRONT ENGINE, HAD ALL HOSES AND SEALS REPLACED BUT...