The toughest trail Ive been on in the video below. Its a down, and back trail. So as you pass each obstacle you know you're gonna have to hit it again on the way back. However, the turnaround point is a beautiful beach cove on Saguaro Lake accompanied by young ladies in bikinis, so its totally worth it.
It was a real eye-opener. Not only did these guys in their buggies and back-halved jeeps do some incredible obstacles, but the pace was fast. One guy was not really cool about me being there the first half of the trip, you can hear him tell his girlfriend I should have taken the easier way at 2:45. He warmed up a little after we got back.
Overall it was an awesome day and by far my favorite trail to date.