It can only be approached from west to east, so keep that in mind when you're choosing where to speed walk from. This isn't really necessary, as it's easy to find - 9 squares east from the northwestern corner of the map. They'll simply reveal the location to you on your minimap.
You can learn that Oasis exists from several locations in the game, none of which appear to be vital to the completion of the quest. Fallout 3 Oasis Walkthrough (Side Quest) - Guide by Carl Click here to return to the Fallout 3 Walkthrough Index Quest Start: Upon discovering the area known as Oasis.
