不擺駕 No Carriage and No Canopy
當時父子四人不擺駕，不張蓋，步行到暴紗亭。他四眾收拾行李，欲進府謝齋，辭王起行，偶見玉華王父子上亭來，倒身下拜。当时父子四人不摆驾，不张盖，步行到暴纱亭。他四众收拾行李，欲进府谢斋，辞王起行，偶见玉华王父子上亭来，倒身下拜。
逐句解 Line by line
There and then the four of them, father and sons, set out no carriage and raised no canopy, but walked on foot to the Gauze-Airing Pavilion.
Two refusals of ceremony, stated as a matched pair. 擺駕 is to set out the ruler's equipage, the whole procession that moves with him; 張蓋 is to raise the state parasol, the canopy carried over a great man's head that announced his rank at a distance. Doing without both, and walking, is a considerable public act — this is the chapter's prince taking off his rank in order to go and ask a favour.
The four pilgrims were packing their baggage, meaning to go into the palace, give thanks for the meal, take leave of the prince and set off, when they happened to see the Prince of Yuhua and his sons coming up to the pavilion, and prostrating themselves.
The timing is the joke: the pilgrims are packing to leave at the precise moment the prince arrives to ask them to stay. 倒 is dǎo here, to fall or throw down — 倒身下拜 is to throw the body down in prostration, the full obeisance. This is the great courtesy that Bajie failed to perform in the audience hall, and the prince is performing it to the pilgrims.
The old prince walks. No carriage, no parasol, no procession — the two refusals are named specifically so a reader knows what he has given up.
And then he prostrates himself, which is the exact ceremony his officials complained the disciples had failed to give him. The chapter has quietly turned its own quarrel upside down.
The pilgrims meanwhile are packing. They have eaten, been thanked, and are about to walk out of the story of Yuhua altogether, which is how close this chapter comes to not happening.