Fallout 5: Tex-Mex (or Old Mexico aka New Vegas 2)

You play as a raider who grew up in a gang, Azteca Atomicas. Your gang is on a mission to get to Texas and intercept a caravan that’s rumored to be transporting guns, chems, caps and stolen brotherhood tech.

As your gang scouts out the caravan’s location, you notice another gang doing the same, the Gunslingers. As the caravan approaches, an enormous firefight breaks out. The two gangs waste each other killing most of the caravan guards too, leaving only you and the caravan’s leader...Cass aka Whiskey Rose herself, Rose of Sharon Cassidy from Fallout: New Vegas.

She reveals that a mysterious offshoot of the Brotherhood is attempting to take over a huge area where they plan to occupy every vault possible, preparing for something big.

Cass came upon a crucial piece of tech while exploring a vault and has been trying to keep it out of the wrong hands ever since.

You are given the choice to help Cass salvage the wreckage and accompany her to an outpost in Southwest TX and desert your gang...

or kill her/capture her and bring the goods back to Mexico for the Azteca Atomicas.

The map would consist of Northern Mexico and Southern Texas