、。
Night was falling, so we headed home.
Literal
Night [to-に] came-[change-てきた]-[because-ので], we [topic-は] path-home [to-に] arrived.
なってきた combines ~になる with ~てくる ('come to be, gradually become'), giving 'night was gradually falling, (came over us).' 家路につく ('take the road home, head home') is a set literary phrase — 家路 is the home-road, つく is 'reach, arrive.' A slightly elevated register.