Into Hithlum

[Findegil]

But Galin's quote does not apply to the Ered Lómin. It is a discription of the Ered Wethrin, the southern and western fence of Hithlum.

About the Ered Lómin quote to look at both from The Silmarillion.
First after the Dagor Aglareb:
"When nearly one hundred years had run since the Dagor Aglareb, Morgoth endeavoured to take Fingolfin at unawares (for he knew of the vigilance of Maedhros); and he sent forth an army into the white north, and they turned west and again south and came down the coasts to the Firth of Drengist, by the route that Fingolfin followed from the Grinding Ice. Thus they would enter into the realm of Hithlum from the west; but they were espied in time, and Fingon fell upon them among the hills at the head of the Firth, and most of the Orcs were driven into the sea. This was not reckoned among the great battles, for the Orcs were not in great number, and only a part of the people of Hithlum fought there."

Second from a few years after the Dagor Bargolach:
"Battle was joined upon the very plains of Hithlum, and Fingon was outnumbered; but timely help came from Círdan. His ships in great strength sailed into Drengist and there landed a force that came up in the hour of need upon the west flank of the enemy."

This shows clearly that the Ered Lómin was passable for troups. I think, both the Orcs and Círdans people used the pass or passes that Feanor and Fingolfin had used. And the first quote shows that these passed were at the head of the firth of Drengist.

Respectfuly
Findegil