Nothing in the nature of Plot Notes exists for New Chapters I, II, & III – naturally enough, given that Tolkien had already long since completed the story and instead was now trying to bring it into accord with its sequel, and his own revised opinions about how such a story should be told. However, a single page of notes [Ad.Ms.H.11] does exist, clearly meant to serve as reminders to Tolkien of points he had not yet addressed in this revision, and I give those here:

Since the Fifth Phase was abandoned at this point, ultimately none of these points was resolved. The fate of Rohald is suggested by Tolkien’s note at the end of New Chapter III (see page 803 above); since the horse was from Rivendell, Gandalf presumably left him there when Thorin & Company departed and headed up into the mountains. The musical instruments are a thornier issue, since these notes indicate Tolkien’s dissatisfaction with the text as it stands but give no hint of how he might have resolved the problem. Given his attempt throughout the 1960 Hobbit to reduce the whimsy and comic touches of the original, however, it seems likely that in the end this bit of dwarven exuberance would have been sacrificed to probability and all but the most portable instruments deleted.