Retrieve the GECK for Arroyo

This is the main starting quest given to the Chosen One at the beginning of Fallout 2.

There are two GECKs in the game, One at Vault 13 and one at the Final Base.

In order to retrieve the GECK from Vault 13, there are two ways. Note that a possible bug prevents this route. At the Vault you will have to either negotiate with or dispose of the inhabitants, which will require the Vault-Tec Computer Voice Module, which can be obtained from Eldridge in New Reno Arms, or Vault 8. Or, much simpler, just get to the Oil Rig. In the floor trap room, in the "safe room" all the way to the right, a GECK can be found in one of the lockers. You're missing out on a lot of XP, but you keep the deathclaws alive...until you talk to them again. However, Killap's faithful users can get around this.
 * One must make his way to NCR, talk to the Sheriff Dumont (standing on the corner in NCR Downtown), tell him you're looking for "honest work." He will then refer you to Westin (the entrance to his ranch is appropriately enough at the west end of town). Take the quest to investigate raids on his brahmin and then track the perpetrators (talking deathclaws) back to Vault 13.
 * Alternatevly, take Tandi's quest to clear/negotiate with with the squatters in Vault 15, kill or leave Darion (your choice based on which quest you are doing)on Level 3. Opposite from his room is the computer room. One of the computers has information on Vault 13, although it requires a decent Science level.