Well you have Frodo and Sam followed by Golem going to mount doom Merry and Pippen captured by the Orks and then meeting Treebeard. Then Gimly Aragorn Legolas looking for them going through the countryside preparing for the siege of Minas Tirith. The Saruman storyline. But it flows.

Alternately: - Gollum going to Mt Doom stalked by Frodo/Sam - Orcs going to war but Delta force (Merry+Pippen) gets local guerrilla forces up against them. etc..