Trooperman37 said:

I would think:
-Star Wars (original cut)
-Empire Strikes Back (original cut)
-Return of the Jedi (original cut)
-Caravan of Courage
-Battle for Endor
-The Force Awakens

If you wanted to do an alternate-quality marathon, you could try:
-The Phantom Menace
-Attack of the Clones
-Revenge of the Sith
-The Holiday Special

Each set you’ll notice has its own flavor. Namely, one set is good and another is not so good, or rather, bad.

Your first set puts the best movies first, while your second set puts the best movie last. While I can appreciate the concept of a “worst of the worst” Star Wars marathon, you’ve got to put that sort of marathon in order of quality so that you can bail out at any point, knowing it would have only gotten worse if you’d kept watching.

So I’d recommend going straight chronological on that one too, so that you have the chance to hear Leia sing, but have the option to quit before the marathon hits rock bottom with ROTS.