noun
a great distance; a long journey to a faraway place
Literary yojijukugo evoking the image of a giant bird (鵬) flying ten thousand miles; used for vast distances or ambitious, far-reaching journeys.
彼の夢は鵬程万里、世界を舞台に活躍することだ。
His dream is a great journey across the world, making his mark on the global stage.
前途洋洋 means a bright, promising future ahead, while 鵬程万里 emphasizes the vast scale or distance of the journey itself.
From Chinese legend: 鵬 is a giant bird that can fly ten thousand 里 (miles) in one journey. The phrase is used metaphorically for a great distance or an ambitious undertaking.