Heading South On A White Bronco

 is a secret Achievement/Trophy in Red Dead Redemption

Description
"Evade the US Marshals while riding the Hungarian Half-Bred horse in Single Player."

Acquisition
The trophy/achievement is earned by evading US Marshals while riding a Hungarian Half-bred horse in Single Player or Free Roam.

US Marshals seem to be called out once a bounty reaches $2500, however lower bounties have been confirmed if the player's fame status cuts bounties in half.

Tips and Tricks

 * One must break a Hungarian-Half Breed found in Mexico. They can be found in the wild near the "Coronas" of Diez Coronas or south east of Escalera (marked on the in-game map by three galloping horses). Once you have broken one, either take it to a hitching post to save it or purchase one from a general store.
 * Accumulate a bounty of approximately $2500 (or $1250 if your fame is maxed out) or higher and evade local law. Equipping the bandana will prevent from losing honor without ruining this achievement.
 * The easiest way to do this is to simply enter a town and start slaughtering the townsfolk. Shoot one person to get the attention of the local law enforcement, and then proceed to take them all out. Eventually the town will run out of officers and the wanted level will disappear, leaving only the bounty. This works VERY well in Blackwater, as the town seems to never run out of officers, but they do not come in large groups.
 * A good way to survive the onslaught of lawmen is to take cover behind the counter of the doctor's office in Armadillo. There's only one entrance to the office and it's in plain sight. When a lawman appears, shoot him and go back to take cover.
 * In at least one case a player reported being chased by Marshals with a bounty of only $548 (with fame maxed out).
 * Next, fast travel to Mexico. Then, with a horse at your campsite fast travel back to America. By doing this the U.S. Marshals will automatically spawn on top of the player's position.
 * Immediately start running away from them, using horse pills, apples, and health restoring items as necessary. Once evaded the Marshals, the trophy/achievement should unlock.
 * Go to MacFarlane Ranch, because there are a lot of routes to escape and less officers to chase the player, get their attention and go out from the route they're not coming, use one horse pill and you'll get the achievement/trophy. This achievement can also be obtained in multiplayer. Just get high bounty and you must also have Hungarian Half-bred as mount. Evade the marshals and you get the achievement.
 * When having the horse and the Bandana, go into Armadillo, walk into the Gunsmith's shop, walk past him into the little room in back, equip the bandana, come back to where he is and rob him. Then go back to the back room and just wait for the law. The Pump-Action shotgun is the best way to clear out the lawmen. Only a few will try to come from the back door and that is very few and far apart, most will come through front (2 at a time) and will just stand there by counter, peek around and kill them. Doing this until last lawman is dead. Keeping your bandana on go out side and start killing people until being wanted again, then run inside and repeat... unless the Marshals show up then get on the mount. Once getting away and the wanted is gone, the trophy is unlocked. Also a good and simple way/place to get the Friends in High Places trophy.
 * When in Armadillo go to a room by the outside door. Face the door and jump,this will be able to get on top of the building and shoot everything in sight. The lawmen can shoot but cannot get on to the building.
 * In Armadillo, go in to the Doctor's Office instead of the Gunsmith's shop because there is no back door and officers will generally come in one at a time. If the fame is maxed out, Marshals follow the player with a bounty of approximately $560.
 * Go to Blackwater and enter the train station. Crouch in the only corner with no doors in it. Officers will run in the front door 1 by 1, and, not knowing where you are, be open targets. They come through the back door little, but when they do it's easy to see them coming on the map. I used this for this achievement and Friends in High Places.
 * Go into the bank vault in Armadillo and equip your favorite close-quarters weapon. You should automatically become wanted. If the search area turns gray, just fire a weapon to help the cops find you. Shoot the cops as they come in.
 * Another good way to get a bigger bounty is to kill some townsfolk in Armadillo and then go into the back room of the gunsmith and kill lawmen as they come by.
 * A good way to get this achievment is to have a very low or no bounty in Mexico and a bounty of about $1250 in America. Find a Hungarian Half Bred and cross one of the bridges from Mexico to the US. Once you are spotted by the Marshals just turn back to Mexico. Or you could just do the opposite. The point is for the Marshals or Mexican Army to spot you and evade.

Trivia

 * This may be a reference to the police pursuit of O.J. Simpson, mainly the video and statements reporting "a low-speed pursuit in a white Ford Bronco SUV." However, Simpson's white Bronco was actually traveling north on Interstate 405, so this could be an error on Rockstar's part, or there isn't really a connection.
 * This also may be a reference to the film Shrek 2 in which the characters Donkey and Shrek are racing toward a castle and one of the men-at-arms says: "We have the suspects heading south on a white bronco." 'Edit: That line in Shrek is in itself, a reference to the police pursuit of OJ Simpson, so I highly doubt that the Red Dead trophy/acheivement is referencing a Shrek reference to the OJ Simpson chase. The trophy is simply a direct reference to the OJ Simpson police chase.

Achievements/Trophies
The following achievement may be obtained in conjunction with this one: