@npiet1: It's a mission called into the sunset. I looked it up and it's an achievment thing. I'm not interested in any more silly side-missions. If I'm done the game, why doesn't it just cut to credits? And if I HAVE to earn this trophy thing, what's the fastest way? It's completely unclear what I'm supposed to do.
@playerp: You're not familiar with open-world games I gather? They never "end" like other games will do. Maybe you'll get an end-credit or something, but when that's done you're back in the game-world and can continue playing. Doing side-missions you haven't done, collect bountys, doing challenges etc. etc. Into the Sunset is an achievement/trophy you should receive after the last story-mision: "The Last Enemy that shall be destoyed". It ends with John Marston dying and end-credits. After the credits you play his son Jack. You start off at John's grave and you're back in the game-world doing whatever you please. There are no more endings and you can safely turn off the game and play something else if you want to.