Or to put the title in another way: "How do go about writing multiple plot branches and maintain stories that split from a main narrative? Do you write each part of the story through on each "path" or do you write them all as a running chronology of events to make the interconnections in the narrative deeper?" I have a late-branching narrative and while these "branches" can be effectively called "alternate endings", they are different since they are not about a climatic showdown of any nature, just the role a protagonist takes in life. I was wondering how other people handle writing such works.
I write each moment and each character as their own. I will consider character arcs, and I will consider main plots. And often, especially in the most character-driven ideas, form the latter somewhat out of the former.
I think of it as a > symbol. I switch back and forth between each side of the symbol frequently enough that neither are forgotten, showing how the separate stories slowly draw together as various characters move towards a final confrontation. I build up dramatic tension and irony as characters on one path proceed unaware of knowledge they could have gained from the other, and then at the climax, I finally set off every Chekhov's Gun as the paths intersect and the story becomes a unified whole. That's the theory, at least. I find these structures difficult to write, so I can have trouble finishing them. As a side note, this is something video games are great at, since they can let the player control when to switch over. A lot of great games allow the player some freedom to choose which stories to view in which order, like Trauma Team or Live a Live.