Follow Up to the Blue Mountains Question - Gundabad

[Kuruharan]

Since the Iron Hills were settled after the trouble the Dwarves had had with dragons

Actually, the Iron Hills had been inhabited by the Longbeards since the First Age according to Of Dwarves and Men

you first had to wipe out the hosts of goblins there

The dwarves already had. They wiped out the orcs living there during the War of the Dwarves and Orcs. That's why the whole thing is puzzling to me.