Alright, I found something that worked very well to get into the Strip for free, no glitch. (I'm not one to use glitches in FO.

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First you have to have an NCR uniform; I grabbed one early on from Primm because I thought they looked cool. Anyway, before you can go to the strip there's a Mojave Camp or something like that outside of the Strip (By the "New Vegas" welcome sign). You need to go in there and there's a building that has a monorail that goes back and forth between the camp and the Strip. After you enter the building head up the left flight of stairs and put the uniform on (If you don't have the uniform on the guards by the monorail door will kill you) after you go up the stairs take another left there will be two armed NCR soldiers guarding a door; if you have the uniform on they'll wave you through. Take the monorail to The Strip and you'll exit by The Tops Casino.
Sorry if that doesn't make too much sense but I got into New Vegas when I was level 5 playing VeryHard/hardcoe Mode because I wanted to see The Strip, but that's how I did it.