Idk what it is with Bioware games, but I generally just can't get into them. This is the 3rd time I've tried to play this and I've gotten further than before, but it just doesn't seem to get any better. Same with the first Dragon Age.
The planets you land on just feel barren. There's one explorable location on each and a lot of them are only a few rooms where you might get into a firefight or two. I don't see what the hype over this game was all about.
I assume it'll be sometime after his son died and after Rick and Michonne found him holed up in that building with all the traps. But why would he ever go to Mexico? Did he just decide to wander off in a random direction one day? I can't imagine any motive that won't seem like something the writers just pulled out of their ass.