Alright, to sum it up, I suppose I'm pretty far into the game. I've unplugged Mr. House, but didn't kill him. I installed Yes Man into Mr. House's computer so he (and I guess I) have control now. And on top of that, all my other quests are complete. Yet, no new quests have popped up. Where do I go from here?

Fortification Hill (i.e. you take up Caesar's invitation).

Not necessary.

Try going back to Mr House and killing him, that might update NCR's quest.

Either will probably work.