THE PLT DEPD JULESBURG, CO, BTN 1830 & 1900 MDT. HIS ORIGINAL DESTN WAS CASPER, WY, BUT DUE TO WX, HE FLEW TO BILLINGS, MT & LNDD AT ABT 2200 MDT. AT ABT 2347, HE TOOK OFF WITH ONE PAX ON A FLT TO BROOMFIELD, CO. BFR TAKEOFF, HE WAS ADZD THAT CLOUD BASES WERE AT 9000' MSL; HE REPLIED THEY WOULD NOT BE FLYING THAT HI. WHILE EN ROUTE, THE PAX NOTED THEY WEREAT 7300'; THE PLT EXPLAINED THAT WOULD BE ABT 2800' TO 3000' AGL. LATER, THE PAX NOTED THEY WERE AT 7500'; THE PLT SAID THAT WOULD BE ABT 2400' AGL IN THAT AREA. AT ABT 0200 MDT, THE PAX BCM SLEEPY & DOZED; WHEN SHE AWOKE, SHE BELIEVED THE PLT HAD DOZED ALSO. SHE NUDGED HIM & HE STRAIGHTENED UP, SLAPPED HIS FACE & SAID HE WAS FINE. LATER, THE PAX DOZED AGAIN& AWOKE WHEN THE ACFT IMPACTED THE TOP OF RISING TERRAIN (ELEVATION APRX 7000'). SOME 4 TO 5 HRS LTR, WHEN BOTH REGAINEDCONSCIOUSNESS, THE PAX ASKED THE PLT IF HE FELL ASLEEP. HIS RESPONSE INDCD TO HER THAT HE HAD. THE PLT DIED AT ABT 0900.WX DELAYED A SEARCH. THE ACFT WAS FND IN LATE AFTERNOON AFTER THE ELT SIGNAL WAS RCVD BY SATELLITES & OVERFLYING ACFT.