Stanza 2 Summary

Get out the microscope, because we’re going through this poem line-by-line.

We were very tired, we were very merry—
We had gone back and forth all night on the ferry;

Wait, we've heard this before, haven't we? Six lines ago, to be precise.
Repeating the first two lines of the first stanza allows St. Vincent Millay to create a sort of emotional center within her poem. Sure, the speaker is unraveling memories at a break-neck pace. Sure, every line's going to have some sort of new action. But these first two lines become the starting point of each of those memories.
It's sort of like when you and your friends start telling stories that begin with the phrase, "Remember that time when…." This is "that time when we spent the night on the ferry." Interestingly, though, what the speaker emphasizes is not the action (the ferry-riding) but the emotions – the tiredness and merriness make this night memorable for her.
If you've ever had a moment which just feels good, chances are that you'll remember it. They're the moments that call for big, sweeping musical accompaniment in movies. But in real life, they tend to be built out of tiny, trivial details. It's not important, really, what the moment is. It's how you feel while you re-live it that counts. At least, that's what our speaker thinks.

And you ate an apple, and I ate a pear,
From a dozen of each we had bought somewhere;

Speaking of trivial details: they eat fruit. How much more mundane can you get? Our speaker, however, seems perfectly thrilled to be eating pears and apples on a night ferry. Hey, there's no accounting for taste!
This is the first time, though, that we get a better sense of who the poem's "we" could be. "We" turns out to be two people: the speaker and "you," someone who accompanies the speaker on her nighttime rambles.

And the sky went wan, and the wind came cold,
And the sun rose dripping, a bucketful of gold.

Here's where the poem takes off on a fanciful flight of the imagination. You can almost see the transition into cartoon-like colors from the dull, cold, uncomfortable world of yesterday. It's like that moment in The Wizard of Oz when we suddenly switch from black and white to the wonders of Technicolor.
We get the sense that our speaker knows just how over-the-top her description actually is. After all, a "dripping" sun and a "bucketful of gold" draw attention to the oozy, schmoozy language of the speaker as much as they serve to describe the sunrise.
Still, if this is going to be a night to remember for the rest of our speaker's life, she might as well use language that will make it memorable!