Ten thousand 里 of hills and rivers, parting the mist and the sunset haze to press forward;

撥煙霞而進步 — pushing the vapour aside to take a step. The verb is the one for parting a curtain with your hand. 進步 is now the ordinary modern Chinese word for progress in the abstract. Here it is literal: putting one foot in front of the other.

a hundred rounds of cold and heat, passing through frost and rain to leave a track ahead.

百重 — a hundred layers, a hundred rounds. Its second character is read chóng, a fold or a repetition, not zhòng, heavy, which is how the bare chain takes it. And it sits opposite 萬里 in the matched line — ten thousand lǐ of distance against a hundred rounds of season. Space and time, one in each half.

His sincerity weighed heavy and his labour light; his seeking was deep and his wish was to arrive.

誠重勞輕 — the same character as the line before, and now it is zhòng, heavy. Two lines apart, two readings, and the difference is between a hundred rounds and weighing heavy. The balance is the point: sincerity heavy, hardship light. He did not think the walking counted for much.

He travelled the western regions round, fourteen years.

And here the novel edits history. The transmitted preface says seventeen years, which is what the historical Xuanzang was away. This edition prints fourteen, which is how long the novel's own pilgrim has been on the road. The book has quoted a genuine seventh-century document faithfully for forty lines and then reached in and changed a number so that it agrees with the story around it. It is the same fourteen the Tang monk gave the emperor two blocks ago, as fourteen rounds of cold and heat.

He went through foreign countries to the end of them, asking and seeking the true teaching.

窮歷 — to exhaust by traversing, to go through to the end. The verb is the one used earlier for what the wise cannot do to the invisible. 詢求 — asking and seeking. He is described as an interviewer, going about the question.