Red dead redemption trophy help? :(?

Ok well im trying to get all the trophies on rdr but i am stuck on one of them. It's the friends in high places trophy were you gotta use a pardon letter with 5000 or more bounty. Now ive looked up a lot of ways to do this but none of them are working for me and some of them just take way to long. Ive had the most luck on this one roof in mexico. I just like went on a huge killing spree but as soon as i get to 3500 i die EVERY TIME. its getting really frustrating. Any tips on how to get this trophy easier?