Once I get home, I'll try to dig up the video of my friends and I doing this same thing from the railroad bridge near KPSP and post it. That swing is pretty huge, leaving you well off of the water when you are done swinging. The fun part is rapping off the end of the ropes and taking the ~40 foot plunge into the Green River below.
Anyone wanna give it a try? I have a friend who lives across the street so we can park without the RR seeing us