ABT 20 MIN AFTER TKOF, THE ACFT CRASHED IN VMC CONDS, APRX 26 MI ALONG THE ROUTE FM TUCSON TO LAS CRUCES. INITIAL IMPACTOCCURRED WITH THE L WING HITTING THE TOP OF A YUCCA PLANT AS THE ACFT WAS IN A SLGT NOSE DOWN, L WING LOW ATTITUDE. JUSTBYD THIS POINT, THE ACFT CONTACTED THE GND & SKIDDED ABT 90' BFR HITTING A SCRUB TREE & COMING TO REST WITH EXTSV DMG. THE THROTTLE WAS FND AT IDLE, MIXTURE AT IDLE-CUTOFF, CARB HEAT WAS OFF & THE FLAPS WERE EXTDD 10 DEG. NO PREIMPACT MECHPRBLM WAS FND. THE ENG RAN NORMALLY DRG AN OPNL CHECK. NO WITNESSES WERE FND. A CAMERA WAS FND WITH FILM EXPOSED ON A PREV FLT. AFTER DVLPMNT, IT HAD IN-FLT PHOTOS OF A TRUCK & A TRAIN TAKEN NR GND LVL. THE TRAIN WAS IDENTIFIED. ITS CREW RECALLED SEEING AN ACFT MAKING LOW PASSES AT THE TRAIN EARLIER THAT DAY (COINCIDING WITH THE PLT'S PREV FLT). PEOPLE, WHO KNEW THE PLT, SAID HE SPOKE OF 'DIVE BOMBING' SEMI-TRUCKS & TRAINS, FLYING UNDER PHONE LINES, LNDG AFTER INTENTIONALFUEL EXHAUSTION & MAKING A LNDG IN THE DESERT. ACDNT SITE WAS NR A RAILROAD, INTERSTATE HIWAY & MOVIE SET (OLD TUCSON).