Commentary on the part 1: Supremely funny book. I might be stealing from what I have read elsewhere, but I think its greatness is in the characterization (therein lies my reasoning for skipping the interpolated novels and long discourses on knights errant). The insanity of Don Quixote paired with the naivety of Sancho make the book.
I think the plot of the book is secondary. At least in the first part, it seemed to end abruptly, or at least anticlimatically. I suppose the main thrust of the story is Don Quixote's friends trying to cure him. But, as I said, the pleasure of the first part is the madness of Don Quixote, and I think Cervantes just needs an adventure in which to exhibit our ingenious gentlemen. He just needs sanity to contrast with the madness of Don Quixote, and, in the case of Sancho, average-ness to contrast with his simple mind.
Unfortunately, I've not yet begun the second part. I'm having to read "Cry, the Beloved Country" for the Africa trip. I have to be done with it by Sunday, so I will start reading Don Quixote soon after that.
Note to Sarah and Andrew: Mike and I are reading the Grossman translation, which was done about 3 years ago - I didn't know if you guys have picked it up yet.