Well, long story short - I had gotten to Legate's camp to complete the end of the game. But silly me, I had accidentally saved over my game BEFORE the whole battle. Pretty much I was stuck moments before the very end where the NCR comes crashing through.

Somehow, I found a way to get out of Legate's camp and away from the bridge and the main mission. Ended up back in the "regular world." Don't know if I was supposed to be able to do that -- however NOW I am unable to fast travel -anywhere-. Whenever I try, the message pops up as "Fast Travel from this location is unavailable," regardless of where I am. Do I have any hope of fixing this glitch, or am I doomed to walk everywhere?

Because you're on console, I can't think of much you can do. Take this as a lesson though. *points to sig*

When playing an RPG, SAVE.

I figured as much. And like I said, I had saved a special game outside of the main mission, but had a durh moment and saved right back over top of it in the camp.

Think when the DLC's come out, it might help fix the glitch?

Possibly. Traveling to a new area may reset the no fast travel tag. You've tricked the game into thinking you're still in Caesar's camp, but traveling to a new area altogether may fix that. I wouldn't hold my breath though.

Totally knocked my pride from being sneaky down a few notches. :sadvaultboy:

It's not a glitch so I doubt it. It gives you the warning before you start the mission, you accidentally saved over your previous save, I'm not sure which part you think is a "glitch", it doesn't want you to fast travel away from the final mission, which it believes you to still be apart of as you agreed to start it. Can you go back and finish the game? Your best bet, finish it, enjoy the ending, and start a new game, maybe as one of Caesar's boys.

No, it is a glitch. He's managed to get out of the camp. (Unless I've misread this?)

But you do raise a good point. He's technically not supposed to be where he his, so I doubt he'll be able to get into the DLC's.