According to Wikipedia, "Fallout 3 picks up 30 years after the 'setting' of Fallout 2 and 200 years after the nuclear war that devastated the game's world. In the game the player is a vault-dweller whose father goes missing shortly after his or her 19th birthday, and who must venture out into the Wasteland around Washington, D.C. to find him."
If you mean after you have finished the main quest line then no you have to load a previous save.
No, When you complete both Fallout 3 or Fallout New Vegas you are not able to free roam the wasteland.
Occasionally Fallout: New Vegas will freeze, but not as frequently as Fallout 3.
fallout: new vegas 2 I've heard.
Follow the main quest line or head NorthEast of Goodsprings.
Fallout: New Vegas
Fallout New Vegas is the fifth installment in the Fallout series. It is for the Xbox 360, PS3, and the PC.
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.
There are no drivable vehicles in Fallout New Vegas, unless added by a mod.