Looking at your travel plans, this post may be coming too late to help you. Hopefully you meant, next Friday to Sunday. In that case, here are some thoughts:
1) Vegas is not as anonymous as you would think. Fortunately, you hail from NYC so the odds on running into someone you know is somewhat diminished. If you were an LA person...forget it.
2) For some degree of privacy, stay in a hotel that is either a) one step above or b) two steps below your normal economic class. Ie: If you are middle class, and normally associate with middle class individuals, either book a suite at the Wynn.....or a room at the Excalibur. The chances of running into anyone you know are diminished.
3) There are numerous threads on here with restaurant recommendations. I would suggest an off the Strip place...once again improving your odds.
4) If you are a slots player, only play machines away from the entrance/exit to the casinos. Remember, you want to be invisible.
5) No cameras, no cameras, no cameras. (Pretty self explanatory).
6) Take her to one of the Downtown Vegas casinos. More locals hang out there....your odds of discovery decrease.
7) Avoid the taxi line at the airport. Have a car waiting for you. You will be in this line for an eternity. Hundreds of people will walk past you. Why take a chance?
8) Same story for baggage claim. When you arrive at McCarren, tell the "secret babe" that you are hungry. Dip into a restaurant at the airport and blow(no pun intended) 25 minutes. Then, go to baggage claim, collect your bags (they should be on the belt) and get into your waiting car. (See #7).
9) Take her on a helicopter tour of the Grand Canyon. Yes, this will cost you some bucks. But a) you will look like a hero and b) your chances of being discovered are remote.
10) Remember to have a good "escape story". You run into a neighbor? This is Daisy, my colleague. We are here on a convention. You run into someone at the airport? This is my colleague Daisy. Our flight was cancelled....we have a few hours to blow (again,no pun intended) and are heading down to the Strip. You run into your wife/significant other? I have no idea who this crazed B**ch is !!!

Good luck. Let us know how it turns out...