FLT CREW OF C560 GETS DISTR BY A CONFLICT WITH AN UNCTLED GOLF CART WHILE DEPARTING THE RAMP AND INADVERTENTLY ENTER RWY 23 AT ZZZ. DEPARTING ACFT; AT TOO HIGH A SPD TO ABORT PRIOR TO IMMINENT CONTACT; CONTINUES TKOF AND AVERTS COLLISION BY MOVING TO THE R SIDE OF THE RWY.

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WE WERE CLRED TO TAXI FROM THE RAMP TO RWY 23 AT ZZZ. FLAGMAN TURNED US OFF RAMP TO R (HAD BEEN PARKED FACING S). SHORTLY AFTER WE TURNED AROUND; SIC FIRMLY STATED 'TUG!' AS HE SAW AN UNLIT 'TUG' MOVING ACROSS IN FRONT OF US. I APPLIED THE BRAKES AS A GOLF CART WITH NO VISIBLE LIGHTING CROSSED FROM R TO L IN FRONT OF US. NEXT THING WE KNEW WE WERE TURNING RIGHT ONTO THE RWY; AS AN ACFT WAS ON TKOF ROLL. SIC YELLED 'STOP!' AND I STOPPED. (ACFT ON TKOF MOVED OVER TO R SIDE OF RWY.) NOSEWHEEL AND L MAIN GEAR OF OUR ACFT WAS ON RWY WHEN STOPPED. GND CTL TRIED CALLING TO SEE WHO WAS ON THE RWY. WE STATED OUR CALL SIGN 3 OR 4 TIMES BUT GND COULD NOT HEAR US ON COM #1. AFTER A COUPLE OF MINS SIC CALLED GND ON COM #2 AND THEY GAVE US TAXI INSTRUCTIONS OFF THE RWY. UNLIT MOVING OBJECT AT NIGHT WAS A FACTOR; AS IS THE ARPT LAYOUT -- TXWY TO 23 IS NEARLY CONNECTED TO RAMP SO IS EASY TO MISS THE TURN ONTO THE TXWY RATHER THAN THE RWY. NO COLLISION RESULTED FROM THIS OCCURRENCE. SUPPLEMENTAL INFO FROM ACN 653691: CONTRIBUTING FACTORS WERE: 1) NIGHT. 2) TUG/GOLF CART OPERATING ON RAMP/TXWY. 3) POOR ARPT LIGHTING AND SIGNAGE. 4) PROX OF RAMP TO TXWY. WHILE WE WERE ON THE GND AWAITING TKOF CLRNC; WE OBSERVED ANOTHER ACFT TAXI FROM THE RAMP AND MISS THE TXWY. THAT ACFT ALSO HAD TO BACK TAXI ON THE RWY. CALLBACK CONVERSATION WITH RPTR ACN 653692 REVEALED THE FOLLOWING INFO: THE CAPT/RPTR ADVISED THAT ZZZ; NORMALLY UNCTLED; IS ANNUALLY PROVIDED A TEMPORARY CTL TOWER. THUS; THE EXISTENCE OF A TFC 'AUTH' IS NOT A ROUTINE CONDITION. SHE FELT THIS PROBABLY CONTRIBUTED TO THE LACK OF TFC AWARE ON THE PART OF THE VEHICLE DRIVER AND HIS OR HER FAILURE TO CEDE RIGHT-OF-WAY TO TAXIING ACFT. ALTHOUGH THE CAPT HADN'T A SPECIFIC MEMORY REGARDING SIGNAGE; THE COPLT FELT IT WAS INADEQUATE. BOTH FELT THE NARROW UNIMPROVED AREA BTWN THE RAMP AND THE EQUALLY NARROW PARALLEL TXWY CONTRIBUTED TO THEIR LOSS OF POSITIONAL AWARENESS.