Complex sentence: The arrival of the railroad in 1881 brought the first real activity to the area, two years later when the gold rush hit nearby Cœur d'Alene the town grew to accommodate the men going over the Murray trail to the mines.
Split into simpler sentences: The arrival of the railroad in 1881 brought the first real activity to the area. Two years later, when the gold rush hit nearby Cœur d'Alene, the town grew to accommodate the men going over the Murray Trail to the mines.