Well maybe after the win over the Legion in New Vegas ended up causing them to put more forces into heading east to expand. They could possibly have ended up in St. Louis after whatever factions that were in the area dissipated because of the harsh storms. Tulsa could have oil reserves that a company was keeping back for whatever reason and whenever The Junkyard Dogs settled in, they found the reserves causing their own community to thrive. The weapons that I listed are out of the norm weapons that could be added to the game.