[Lucius Cornelius Sulla]

I wonder where they’ll split the storyline? Or maybe they’ll have some filler after Bilbo returns leading up to the LOTR timeline.

The discussions I read on this subject say the break will occur after the end of the Hobbit, with the 'filler' you mentioned coming from some of Tolkien's appendices on the 60 years between then and TLOTR. There is another theory that the story which goes on in the background of the Hobbit, involving Gandalf's meeting with the White Council, and their actions against Sauron's gathering of strength in Mirkwood Forest could be included.

[fnord]

either one of those would be good. I’d especially like a longer look at life in the Shire.