I dont think you can. As you can have many quests on the go, just choose which quest you'd like to do and leave the ones which you dont want to do.
if you mean rex you get it when you recruit him
Follow the main quest line or head NorthEast of Goodsprings.
Occasionally Fallout: New Vegas will freeze, but not as frequently as Fallout 3.
fallout: new vegas 2 I've heard.
Fallout: New Vegas
Fallout New Vegas is the fifth installment in the Fallout series. It is for the Xbox 360, PS3, and the PC.
If you mean after you have finished the main quest line then no you have to load a previous save.
Fallout new Vegas
No, you can't get married in Fallout: New vegas, but you can have sex in the game :)
fallout new Vegas will be on PlayStation 3 and Xbox 360
In my opinion, Fallout 2.
He is at the Old Mormon Fort, which is in Freeside, on the outskirts of New Vegas. It is not a marked location on the map, just part of the Freeside area.