The reason you never see Doc Mitchell outside is because he’s under house-arrest for being a pervert.

Anyway I started playing New Vegas because I watched a video that told me New Vegas is great (it was a good video except for all the spoilers but I suppose that is my fault for not having decided to play New Vegas a decade ago), and after extensive fiddling with mods and roaming the wasteland I can say that yes, the video was quite correct, New Vegas is great.