The best weapon against any boss is the small chainsaw that you can take after defeating the crazy clown, that small weapon was very handy, and the guys in the jeep with a sniper rifle and a little of patience you can take that problem, and they appear two times in 72 hour mode, so i reccomend that you keep 2 sniper rifles and use them to take down that guys, also you can use either a sniper rifle or a shotgun to beat the girl in the motorcycle, its easier than other options...