A B733 CREW; DURING TAXI FOR TKOF AT ELP; ENTERED THE OVERRUN OF AN ACTIVE RWY.

Narrative

UPON CALLING FOR CLRNC TO TAXI; WE WERE GIVEN THE INSTRUCTIONS TO 'TAXI TO RWY 4.' WE BEGAN TO TAXI OUT FROM THE GATE WITH THE INTENT OF STAYING ON THE TERMINAL RAMP ALL THE WAY. HOWEVER; WHEN WE CAME AROUND THE CORNER; ANOTHER ACFT WAS BLOCKING THE TERMINAL RAMP SO WE CHOSE TO EXIT THE RAMP AT TXWY G AND TAXI UP TO TXWY E TO TXWY F IN ORDER TO GET TO RWY 4. BEFORE WE EXITED THE RAMP; THE CAPT ASKED WHETHER I THOUGHT IT WAS OK TO GO THAT WAY. I TOLD HIM THAT OUR INSTRUCTIONS WERE ONLY TO 'TAXI TO RWY 4' AND THAT I UNDERSTOOD THAT GAVE US CLRNC TO GET THERE ANYWAY WE WANTED. RECOGNIZING THAT WE WERE AT ALL TIMES WITHIN BLUE TXWY LIGHTS ALSO GAVE US CONFIDENCE THAT WE WERE OK. 1/2 WAY BTWN TXWY G AND TXWY F ON TXWY F; WE SAW A DC3'S LNDG LIGHTS AS HE TURNED FINAL FOR RWY 8. AT THAT TIME; GND ASKED WHO WAS ON TXWY F. WE LET HIM KNOW THAT IT WAS US AND HE TOLD THE DC3 TO GO AROUND. WE RETURNED TO THE RAMP AT TXWY F AND CONTINUED TO RWY 4. THE TWR GAVE US A NUMBER TO CALL AFTER TKOF. THE CAPT CALLED WHEN WE ARRIVED IN PHX AND WAS TOLD THERE WAS NO PROB WITH WHAT WE HAD DONE. SUPPLEMENTAL INFO FROM ACN 530780: AFTER TKOF; DEP GAVE US A PHONE NUMBER TO CALL. WE DISCUSSED THE PROB AND HE SAID THERE WAS NO LOSS OF SEPARATION. HE ALSO SAID HE WAS IN ELP FOR 13 YRS; AND THE MARKINGS AND DESCRIPTIONS ON CHARTS HAVE ALWAYS BEEN A PROB IN THAT AREA.