Check out the 2/4 limit game at the Palms. It has a reasonably low rake.
The Sahara usually has a low entry NLHE tourney going thru the week ($30?)
I have heard good things about the Excalibers NL tables, like low buy-in, loose players.

There are so many places to go, give us a report on what you find.

I would advise trying the breakfast buffet in Harrah's if you are staying near there. I love that place. I've been to Vegas seven times and never ate breakfast anywhere else. If your into shows then We Will Rock You at Paris was really good. The secret gardens in Mirage are worth visiting. Try the rides at the Stratosphere. the Big Shot and X Scream especially. Wouldn't bother with the rollercoaster ride. I'm sure you will have a great time but you will probably feel that four days isn't enough for the first time going there. Enjoy and make sure you stick a few bucks in Megabucks, you never know, you might just get lucky.