Pilgrim asked: "Eight Rules, how heavy is your baggage?"

行李: 行 = xíng. 多重: 重 = zhòng, "how heavy" — not the chóng of "again," which turns up three lines below.

Eight Rules said: "Brother, this baggage I shoulder day after day — I really don't know how heavy it is."

挑著: 著 = zhe, the action going on. 倒也不知: 倒 = dào, "yet, actually." 多重: 重 = zhòng. A perfect Bajie answer: he has carried it every day for years and has no idea what it weighs, because he has never once put it down willingly.

Pilgrim said: "Divide that one load of yours into two: one load you carry, and one load give this emperor to carry.

Pointing 那 = nà. 擔, a carrying-load and the measure for one, is dàn throughout this line; because 擔 is fixed to the falling tone, each 一 before it stays yí rather than shifting. Rounding-off 兒 = er; 將 = jiāng; 分為 takes 為 = wéi; 著 = zhe.

We'll press on early into the city and see to our business."

趕早進城幹事: 幹 = gàn, to attend to business.

Eight Rules said gleefully: "What luck, what luck!

造化 is good fortune, a windfall. Bajie's delight at halving his load arrives before he has thought about who carries the other half.

When we carried him here on our backs, no telling what it cost in effort;

當時馱他來: 當 = dāng, "at that time"; 馱 = tuó, to carry on the back. 費了多少力, what it cost in effort.

now that he's cured, it turns out he's a stand-in!"

醫活了, cured back to life. 替身 is a stand-in, a substitute — and Bajie means it in the most literal way possible: the man they hauled here as cargo can now carry cargo.

That blockhead played his tricks: he split the baggage apart, then asked the monastery for a flat pole, shouldered the lighter load himself, and had the emperor carry the heavier.

弄玄虛 is to play tricks, to work a dodge. Pointing 那 (那獃子, 那皇帝) = nà; rounding-off 子 = zi. 將 = jiāng; 寺中 中 = zhōng; 匾擔 擔 = dàn; 重些 重 = zhòng; 教 = jiào; 著 = zhe. Given permission to divide the load evenly, he divides it unevenly, and hands the heavy end to a man who was dead this time yesterday.

Pilgrim laughed: "Your Majesty, dressed up like that, shouldering a load, keeping pace with us — does it wrong you?"

著你那般打扮: 著 here is zhuó, having somebody do a thing; the 著 of 挑著 is zhe, the action going on — two readings of one character, three words apart. Pointing 那般 = nà; 擔子 擔 = dàn.

That king hastily knelt: "Master, you are to me as parents who gave me second birth — never mind shouldering a load, I would gladly ply the whip and hold the stirrup, and serve you all the way to the Western Heaven."

Pointing 那國王: 那 = nà. 重生父母: 重 = chóng, "born again" — the parents who gave you a second birth, still the standard Chinese way of thanking someone who saved your life. 挑擔 擔 = dàn. 同行: 行 = xíng, to travel together, not háng. To "ply the whip and hold the stirrup" is to serve as a groom: the king is offering to be a servant for good.

Pilgrim said: "I don't want you going to the Western Heaven — there's a reason within it.

內中: 中 = zhōng, "within." 緣故 is a reason. Wukong has a plan and does not share it, which is usually the sign that one is about to work.

You need only carry it forty li into the city; once we've caught the fiend, you go back to being your emperor, and we go on fetching our scriptures."

挑得四十里: hinging 得 = de; 里 is the lǐ, a Chinese unit of distance left untranslated because English has no name of its own for it. Both 還 = hái. The bargain is exact: forty lǐ of portering, then you may have your kingdom back.

Eight Rules said on hearing this: "By that reckoning, he only carries forty li of road, and old Hog is still the long-term hand!"

還是: 還 = hái. 長工: 長 = cháng — a long-term hired hand, as against a day labourer. Bajie's grievance is that the king has been given a fixed term and he has not.

Pilgrim said: "Brother, no nonsense — get out front quickly and lead the way."

胡說 is talking rot. 趁早外邊引路, get out front and lead on, quickly.