Reddit mentions of History of the Hobbit

this, more or less. the Hobbit, in its original conception, is basically Tolkien deconstructing Faerie stories and making his supercut of all the most classic elements. he just happened to slip in a bunch of references to his own world as well to make it sound unique. Then when it took off, and the publisher wanted more "hobbit stories" he tried to sell them the Silm. They weren't having it, so we got LOTR, and he found himself having to wrap a work he'd not intended originally to be in Middle-earth into his world. he ended up justifying the revised second edition as being the "truer" version of events that Bilbo told Gandalf, while the first is the one he told the dwarves, in order to explain why the ring is passed off as just a bauble in the first edition. but the other discrepancies (stone giants, the staggering differences in behavior you see in the elves, etc) you just have to chalk up to how the piece was conceived.

if this is an interesting topic for you, i cannot recommend enough John D Rateliff's The History of the Hobbit which is i think the single most exhaustive and best researched work on the Hobbit. The history of Middle-earth has great stuff on it too, but Rateliff goes into the wider context of how it was conceived as a faerie story, rather that just its place within the context of middle-earth and the various iterations of its development.

edit: i should have replied to OP, as the person i'm replying to probably knows at least some of this.

http://tolkiengateway.net/wiki/The_Annotated_Hobbit:_Revised_and_Expanded_Edition

I've got both versions and I'd say yes, The Annotated Hobbit has lots of interesting annotations/notes on the text, reprints several rare/unpublished writings by Tolkien (including the longest version of The Quest Of Erebor which had only portions published in Unfinished Tales), more than 150 illustrations and it includes the 1937, and 1951 versions of the text (including the original Riddles In The Dark Chapter) in the sidebars, alongside the 3rd edition text (which is the standard text of all modern editions from 1966+) making it easy to compare the various versions.

If you are interested in learning more about The Hobbit I'd also recommend The History Of The Hobbit by John D Rateliffe which publishes the early drafts of The Hobbit and traces its evolution over the years, with extensive commentary and essays on the characters and themes of the novel:

http://tolkiengateway.net/wiki/The_History_of_The_Hobbit

(Of the three editions, I'd recommend the 2011 one volume hardback, at 960 pages long, it has substantially more content than the other editions):

https://www.amazon.co.uk/History-Hobbit-J-R-R-Tolkien/dp/0007440820/

You could also look at the one volume hardback edition, instead of the paperbacks, as an alternative, as suggested by thornybacon.

https://www.amazon.co.uk/History-Hobbit-J-R-R-Tolkien/dp/0007440820/ref=sr_1_1?s=books&ie=UTF8&qid=1496493727&sr=1-1&keywords=history+of+the+hobbit

Just click the other options. You can get a hardcover for $30.

It's a GREAT set if you're interested in this sort of thing.

If you only want it for those three chapters, though, take a pass. Not sure if they're out there somewhere, but I wager someone has scanned them.