So, I'm brand new to the game, been taking a break from WoW and love how immersive the story is. The Light vs. Dark event drew me in to the game. I've recently hit 65 with my sith sorcerer, but (so far as I can tell) am only about 1/3 way through the original story (just finished Taris). Here's my conundrum: I'm torn between working my way through the original story arcs slowly and skipping to Revan/KOTFE bits for the event achieves and rewards.

Can anyone give me a ballpark on how long it'll take to finish the original story arc? Similarly, from a story point of view is it worth doing ALL the quests on each planet (what I've been doing, but the bonuses are becoming cumbersome), or just sticking to the class progression quests? Can you come back to do them later?

Finally, does anyone know if I start seriously progressing a Jedi character (and for some reason surpass my Sith guy) which character the Light vs. Dark rewards will go to? I care only b/c my Sith guy has some partial sets that I'd like to complete without spending real money/cartel coins.

Thanks!