OK, I`ve done the Render Unto Cesar Ouest and tried to get back into Vegas at the North entrance, but the damned door is locked and I need a key.I`d also sent Boone to the Lucky 38, where all my other companions are and he is standing outside the door also. I`ve been in the Strip a bunch and have even been banned from gambling in all the casinos due to my prowess at blackjack. How do I get back in to confront House? Thanks!

I even called in my favor from the King to get a forged passport in, but no luck

I did the same mistake in asking the king for a fake passport ( you're going to need to hold onto the favor for an ncr quest) but you can go into the strip by wearing an ncr armor and heading inside for McCarran and using the monorail. There 'is' a vegas key in the game but the irony is that you're the one who has to give them out for a quest (hiring for the tops I believe) along with a business card.

Yea, the monorail in NCR armour worked. Had a nice chat with Mr. House face to face. Thanks Sagameister!