I'm back in the US so I should be able to do more regular updates now. Two more Chogonka posts and then 1 or 2 for the Chogonka-den and we'll be back to the actual Genji; hopefully my readership will go above 1 view per post after that. :-) I will try to get the last Chogonka posts up relatively quickly.
(The Daoist priest) searched up in the blue sky, and down in the yellow springs.
But in the vastness of both places, he did not see her anywhere.
Just then he heard about a mountain of sages above the sea,
- 仙 here is probably more specifically the Daoist "immortals" or supernatural beings.
The mountain was in the far off distance, barely visible.
A tower rose brilliantly through the five-hued clouds,
In there, there were many beautiful immortals.
Among those, one had the style name of Taizhen.
- The "style name" is given to someone upon attaining adulthood; Taizhen was Yang Guifei's style name (Wikipedia says it was associated with her status as a Daoist nun before she became Xuanzong's consort). SKT emends the text here (from other manuscripts) to 名玉妃 ("her name was Yufei"); Yufei seems to be a combination of her other names.
She had white skin, and a beautiful face -- this almost had to be her.
The priest tapped on the jeweled door of the western wing of the gold watchtower,
- The images here are taken from traditional Daoist ideas of what the lands of the immortals looked like.
Now then, he had Xiaoyu relay a message to Shuangcheng.
- These are traditional female immortals.
They heard that this was a messenger from the Son of Heaven of the House of Han.
- Another example of Bai Juyi concealing Xuanzong's name by evoking Emperor Wu of Han.
From inside the nine-flowered curtain, she was startled awake from her dream.
- I'm not sure what 魂 does here; it's in Hagiwara and wikisource. SKT has 夢中 instead (without comment), which makes more sense.
She reached for her clothes and pushed aside her pillow, rising in a daze.
The pearl curtains and the silver door opened as she went through.
Her cloud (dark) hair was half-disturbed; she had just awakened from sleep.
- The function of 新 here is to express the idea of having just done some action.
She went down into the main hall, her headpiece not adjusted.
The wind blew her celestial sleeves, making them flutter.
Indeed it resembled the dance of rainbow skirts and feather robes.
- This is a reference back to line 32.
Her jeweled face was sad, and splotched with tears.
(Just like) A single branch of pear blossom, wreathed in spring rain.