ABOUT 1.5 MIN AFTER DEPARTING SPRINGFIELD, IL, THE FLTCREW REPORTED A SLIGHT ELECTRICAL PROBLEM, BUT THEY CONTINUED ON COURSE. ABOUT 33 MIN LATER & A FEW MIN BEFORE THE ACFT SHOULD HAVE REACHED ITS DESTINATION, THE ACFT CRASHED. IMPACT OCCURRED WHILE THE ACFT WAS DESCENDING IN A RIGHT WING LOW ATTITUDE. BEFORE CRASHING, THE PLANE'S HEADING HAD CHANGED ABOUT 180 DEG. A CVR TRANSCRIPT REVEALED THE L GENERATOR (GEN) HAD FAILED AFTER TAKEOFF & THE 1ST OFFICER HAD MISTAKENLYISOLATED THE R GEN. ATTEMPTS TO RESTORE THE R GEN WERE UNSUCCESSFUL. THE CAPTAIN ELECTED TO CONTINUE TO THE DESTINATION RATHER THAN RETURN TO THE NEARBY DEPT ARPT. THE CLD BASES WERE AT 2000' MSL, BUT ATC COULD NOT PROVIDE AN IFR CLNC BELOW3000 FT. JUST BEFORE CRASHING, THE CREW INDICATED A TOTAL LOSS OF ELECTRICAL POWER. THE L GEN DRIVE SHAFT HAD SHEARED. THE REASON FOR THE R GEN NOT TO RESET WAS NOT DETERMINED. THERE WAS EVIDENCE THAT RECURRENT FLTCREW TRAINING DID NOT PREPARE THE CREW TO UNDERSTAND & COPE WITH THE ELEC PROBLEM & THAT FAA SURVEILLANCE DID NOT DETECT THE TRNG DEFICIENCY.