You have to find the 5 Treasure hunters and kill them, Then You get the outfit, Then you go on a mission with them and You go into Mexico
there is no code you have 2 unlock it yourself :)
if you are talking about treasure maps, they are used to find treasure...
No.
there is not one sorry
look in the outfit section of your journal and it will tell you what you need to do
In tall trees
Yes.
Go to the outfits menu in the pause menu and you should see what you need to do in order to unlock that outfit.
You cannot get a gang in Red Dead Redemption, but you can be part of a gang by accepting a wanted poster, then wear the outfit of the gang, then they won't attack you.
If you don't have it already, you can simply purchase it from the PlayStation store, it allows your fame to increase at twice the rate.
Go onto the outfit menu and you will find out what you must do to unlock that outfit.
Yes, you just need to unlock it.