An interesting subject I actually pondered about....

The story goes that the Courier was once negligent. He seemed to live day to day, just doing his job and nothing but, not concerned with morality or the big picture. He failed to realize his own impact on the world and in a way, didn't accept his fate.
Hell, even when he gets shot, he doesn't "accept his fate" in the sense that the badass just gets up and hunts down his attacker for revenge.
Fast-forward to post Lonesome Road, that's when he realizes and accepts his fate. He finally understands that he's involved in something greater than he is, whether he likes it or not, and if he chooses to deny this responsibility, people could suffer. It's time to grow up, and I imagine he does.

Back on that subject, Ulysses also mentions Tunnelers will take the Mojave. To me, this is where the Courier makes his stand. This is where he stops running from reality and faces it. He'll defend the Mojave from the Tunnelers, or die trying. Question is if he'll die trying. In one way it seems like dying to Tunnelers would be taking responsibility; that in order to truly "grow up" he must die to repent for past mistakes. In another way though....this is still the mother [censored] Courier. He just does NOT die. Survived a doubletap at point blank range, survived the Sierra Madre, survived the Big MT lobotomization, survived the Divide, etc etc etc. He's incredibly durable and incredibly lucky.

I'm honestly not sure if he would survive that battle or not. Seems 50-50. Both seem likely. Though tbh, of all the people fighting the Tunnelers, he obviously seems like the best candidate to survive it all.

My character dies after trying to go to the moon. Apparently, the low gravity there results in some unfortunate things for the human body.

I don't think he will die to the tunnelers Longknife. Ulysses made it sound like the tunnelers would go into the Mojave fairly quickly. And the OWB ending makes it sound like the Courier lived a long life as he watched over the Big Empty "for years to come."

I like to think that he'd die alone, but by the time the battle happens, he's inspired and helped so many people that they come to aid him. Thus, by finally taking responsibility for his actions, he's actually saved his own life.
But yeah, I somehow can't picture certain characters not assisting him, such as Ulysses, Raul, Arcade, the Kings (the King himself doesn't seem like a fighter), ED-E and Boone, who should all still be in the general area.

Probably a household accident or cancer (my character smokes alot thanks to mods).

After the Second Battle of the Hoover Dam, my courier continued to travel around helping with the menial tasks left, occasionally fending off yet another Legion hit squad. After a few years he would begin to miss the sense of adventure, hell he even missed those damned hit squads. He would then pack his bags up and set off into the sunset for just one more adventure....

So... How'd he die then?
Heart-attack after he packed his bags or what?

He got an STD from Sarah Weintraub...

Just kidding.

He created a self-sufficient Confederacy in the Mojave which prospered, then returned to the ruins of the Divide with his wife to try to rebuild what he had done.

A few years later, he then revealed to his wife that he must make a stand against the Tunneler threat. It took a lot of convincing, but his wife let him go back to the Divide to face what he had done.

He and Ulysses fought against the endless hordes of the Tunnelers, but there were too many. After Ulysses became injured, they retreated to Hopeville, followed by tens-of-thousands of Tunnelers. The Courier then made a conscious decision to end this once-and-for-all. He ripped off the pip-boy, the legacy of his life (this was extremely painful for his arm), handed it to Ulysses told him to run, and that's exactly what Ulysses did. He detonated the Hopeville Missile Silo (The only dormant missle that wasn't in the original "accident" in the Divide) and destroyed the little piece of his home that was left. He was instantly killed in the blast and it seems fitting that he should die with his home. The Tunnelers were exterminated, and Ulysses inherited the Courier's position in the Mojave.

I can see my latest character asking the think tank to make him one of them, he will do science with them for hundreds of years until his brain will finaly get too old and just give in