Flight Crew Air Transport Pilot (ATP)
Flight Crew Last 90 Days 110; Flight Crew Total 6500; Flight Crew Type 400
Situational Awareness; Confusion
Deviation / Discrepancy - Procedural Published Material / Policy
Flight Crew Took Evasive Action; Flight Crew Became Reoriented
Aircraft; Chart Or Publication; Procedure; Environment - Non Weather Related
After landing Runway 17 at OUN; we experienced some confusion due to runway markings and barricades on the taxi into the terminal ramp.  We passed Taxiway B on our rollout due to another aircraft being on it; and we thought; blocking our exit. We later figured out Taxiway B is the ONLY useable taxiway onto the terminal ramp.  We continued down the runway to taxiway C where we saw a number of barricades and did not think we could taxi any further without getting stuck due to barricades. We then continued down Runway 17/35 to the intersection of it and Runway 3/21. At that point we did not see any barricades blocking our turn onto the closed runway and thought it was open for taxi only. There was a NOTAM for Runway 3/21 stating it was closed; but nothing telling us we could not use it for taxi. Being based elsewhere; we used a closed runway for taxi all the time; it is our norm. As we continued down 3/21 someone spoke to us on the CTAF frequency stating we had to do a 180 and taxi back on 17/35 to get to the ramp. We did; and exited B to taxi across Runway 3/21 to get to the ramp.  Again; there was poor signage and barricades not clearly marking where we could not taxi. That combine with the outbound aircraft on Taxiway B blocking our initial turn off; we did not know how to get to the terminal.
After landing at OUN during uncontrolled operations (tower closed) we became confused during taxi into the ramp. On roll out we bypassed getting off at taxi way B due to an aircraft on the taxi way. Taxi way C appeared to be unusable because of barricades visible from 17. Taxiing further down 17 it appeared the only route to the ramp was down the closed runway 3/21. Someone in the tower recognized our confusion and directed us to back taxi down runway 17 to taxi way B which crosses the closed runway and then taxi way A to the ramp. The crew was aware of all NOTAMs and even had to submit for a waiver due to the displaced threshold and reduces LDA. I spoke with the airport manager following shutdown.
A corporate flight crew reported that after landing on OUN Runway 17 access to Taxiway B was apparently blocked so they taxied to the runway end only to find all exits barricaded. The NOTAMs did not state no taxiing on Runway 3/21.