Books to Movies: Two Towers and Where to Edit

The Two Towers tackles what I consider one of the more interesting problems for films and texts: how does one divide up scenes? 

All viewers likely remember episodes or movies where the scenes appeared to be cut out of order. There's an A&E Nero Wolfe episode which is skillfully cut but I can't shake the instinct that the scenes were originally (according to the script) supposed to go in a different order. Fritz starts an argument with Wolfe about meals; the episode cuts to the next day; in the next scene, Archie is then calming Fritz down as if the argument about meals just occurred. 

Tolkien's text of The Two Towers separates Aragorn, Gimli, and Legolas's adventure from Merry and Pippin's adventures. Meanwhile, Frodo, Sam, and Gollum get their own book!

Jackson naturally sets the scenes with all the above characters side by side. He isn't strictly chronological. Tolkien was well-aware where each of his characters were day by day and hour by hour.

Jackson opts for balance rather than following an exact chronology--in the book, Frodo and Sam in the book reach the gate to Mordor after the battle at Helm's Deep. However, the gap in time would be too much for a film. The viewer needs to be reminded of Frodo's task. 

Interestingly enough, in terms of sustained interest, I think this division of scenes is one place where a film succeeds over the book. Tolkien, I posit, was wise to address Frodo and Sam's story separately rather than trying to juggle all three plot-lines at once. But in the film, the action is straightforward enough, the jump doesn't confuse (the extended version gets confusing since Jackson attempts to include a flashback, which I deem a mistake--otherwise, the three plots are quite seamless). 

But those decisions for scriptwriters can be just as daunting as for novel writers. Chapter break here? Or here? Or here?