In the car, on the drivers side, Under the trim and carpet to the dash.
Remove the cruise control modual in the engine bay. Behind it you'll find a ~1" hole through the fire wall. This leads to a cavity under the wiper. There is a second hole in the internal wall.There may or may not be a rubber grommet in it. Pass the N20 line through both holes.
Good luck. Try fishing a stiff wire through first and then attach it to the N20 line and pull back through.