登高下阪 Up the Heights and Down
沙僧牽馬，八戒挑擔，行者緊隨左右，長老在馬上拱手道：「樵哥，煩先引路，到大路上相別。」一齊登高下阪，轉澗尋坡。沙僧牵马，八戒挑担，行者紧随左右，长老在马上拱手道：「樵哥，烦先引路，到大路上相别。」一齐登高下阪，转涧寻坡。
逐句解 Line by line
Sha Monk led the horse, Bajie carried the load, Pilgrim kept close on either side, and the elder, up on the horse, made a bow with his hands and said, "Woodcutter, be so good as to lead the way ahead, and we will part on the main road."
The formation is exactly the one the chapter opened with, and the difference is that everyone is in their own place. Wukong was doing all three jobs on the first page. 挑擔 takes 擔 as dàn, the pole-load, the last of three in this chapter.
Together they climbed the heights and went down the slopes, rounded the ravines and found their way over the ridges.
登高下阪 and 轉澗尋坡 are two four-character phrases in a row, up and down, round and over — the standard way of covering ground quickly in this novel's prose. The ravine they round is the one Wukong followed the water up.
The party is restored to its proper order and the novel shows it rather than saying it. Sha Monk has the horse, Bajie has the luggage, Wukong walks guard, the master rides. On the first page of this chapter Wukong was carrying all of it alone.
That is the quietest thing the chapter does. It opened with one disciple holding everybody else's job because the party had come apart, and it closes with each of them holding their own again.