How would dwarves reward sentient ravens?
Well, they gave the King of the Eagles a golden crown. Perhaps with food, perhaps with shiny things. They apparently work cheap.
Does anyone want to defend Thorin’s reaction?
Not me. All the defenses of Thorin's actions sound to me like attacks on the Elvenking, and on Bard for allying himself with the Elvenking. Two wrongs do not make a right. Maybe it's also a reaction to the narrator's clear bias, which does not seem entirely justified. But there are so many ways Thorin could have handled it better.
Did the thrush let Bard know what the dwarves were doing? Why or why not?
Again, the thrush's actions are so selective that I see it more as an instrument of providence or the Higher Powers than as a reliable ally.
Why wasn't the adventure over, properly speaking? Why didn't Tolkien just wind things up quickly? What point is he trying to make?
Perhaps he wants Bilbo to have another moment on the stage, as he tries to use the Arkenstone to settle the dispute. And that is an interesting moral dilemma. But ultimately Bilbo's gesture would not have prevented conflict between the free peoples -- only the goblin army united them against a common enemy. I think the Battle of Five Armies is a brilliant surprise ending to a surprise denouement. The problem is the disconnect with the first half of the book. Tolkien doesn't lay the groundwork for this epic battle the way he does in LotR. Bilbo doesn't even take part. Tolkien remedies that in LotR.
The tools are still in good shape? How so? Why haven’t they rusted?
Magic, I suppose.
What was Bilbo thinking while the dwarves were fortifying the entrance? What was he doing?
Maybe he was in a corner secretly looking at the Arkenstone. Maybe he went exploring. Maybe he watched and learned. Whatever he did, he likely stayed out of the way of the dwarves and hoped for the best.
How did the dwarves go about building a stone wall so quickly? How strong would the hastily-built wall have been?
Well, as we see later, it could be knocked down with some good levers. But I'm okay with the ability of dwarves to build stone walls. It's a handy skill. I remember that in the Civil War soldiers quickly learned to build dirt walls over night, and many of those battlefield walls are still standing today.
Are other birds bringing the Elvenking constant tidings, or Bard? Why or why not?
I guess I did ask this before, but it's just interesting to me that they apparently didn't. Again, maybe they just failed to ask -- but if so, that's a pretty bad failure.
Come to think about it, why didn't the ravens or thrush or someone tell everyone about the approaching goblins? Oh, that's right, the goblins stayed underground as long as possible. But surely they could have gotten some advance warning, no? What, did they pop out of the ground a mile away? I don't have an answer for that.
Where did they get their cram? It didn’t come from Lake-town, did it? Didn’t they lose all their other supplies when they were captured by the elves?
It did come from Laketown, I forgot. Sorry.
Where did they get their ladders? If they made them, what did they use for materials? Isn’t the area barren?
I guess Smaug didn't burn up all the ladders.
Does the wide pool blocking the entrance remind anyone of anything?
The entrance to Moria. No giant tentacles, though.
Any other comments about these passages?
No.