I think it's okay if the train barrels onward; no use trying to stop it now, right? Runaway trains are the best kind.

And anyway, (maybe this only applies to me?) knowing too much about my story actually makes me lose interest in it. Writing, like a lot of things, really is about the journey rather than the destination, and I like it when the story still holds some surprises for me.

It sounds like yours will have plenty of surprises to unveil! It sounds amazingly fun.