一路上 can describe physical travel ('along the road') or a figurative journey ('throughout the process'). It's often placed at the beginning of a sentence as a time/place phrase.
usage
一路平安 (yī lù píng'ān) = 'safe journey' — a common farewell phrase. 一路顺风 (yī lù shùnfēng) = 'bon voyage' (lit. 'smooth wind all the way').
