AT APRX 1900 ADT, THE PLT & 2 PASSENGERS DEPARTED NORTH POLE, AK ON A FLT TO PORTAGE CREEK STRIP. DURING THE FLT, HE CONTACTED FLT SERVICE TO OBTAIN WX INFORMATION. HE ASKED FOR & WAS PROVIDED THE WX AT SEVERAL LOCATIONS. ALSO, HE STATED THAT HE WAS REALLY TRYING TO FIND OUT WHAT THE WX WAS LIKE IN 'THE FOOTHILLS OF THE ALASKA RANGE DOWN TOWARD DELTA.' HOWEVER, THERE WERE NO REPORT FOR THAT AREA. AT APRX 1945 ADT, THE ACFT COLLIDED WITH RISING TERRAIN NEAR THE TOP OF A MOUNTAIN RIDGE. REPORTEDLY, IT STRUCK THE MOUNTAIN AT APRX 4050 FT MSL WHILE IN LEVEL FLT. THE TOP OF THE RIDGE WAS ABOUT 4090 FT MSL. NO PREIMPACT/MECHANICAL WAS FOUND. THE PROPELLER BLADES WERE FOUND TWISTED & BENT & THE PROPELLER HAD SEPARATED FROM THE CRANKSHAFT DURING IMPACT. THE 2000 ADT WX AT FAIRBANKS, AK (54 MI SOUTHWEST OF THE CRASH SITE) WAS 1000 FT OVERCAST, VISIBILITY 30 MI, WIND FROM 240 AT 7 KTS, TEMP 51, DEW POINT 47. THE ELEVATION OF THAT REPORTING POINT WAS 434 FT MSL.