Someone told me the trail was similar to running Golden Spike for 20 miles. I'd say that's a decent description. The trail is an endurance test as much as anything. It's not particularly brutal and there are a few bypasses, but you drove all the way there, why take them? I don't usually drive by skinny pedal and the trail didn't require that except for one optional ledge I was on near Buck Island Lake. (I needed some wheelspin to go over some polished granite on some uphill ledges--took me three attempts to give the obstacle the fuel it required)
Things that are suspect would be stock Jeep sheetmetal suspension tabs, XJ steering box mounts on the "frame", and similarly mass produced weak points on a fairly stock rig. Whatever suspension, axle, powertrain or steering weakness your vehicle has will be exposed by the trail (any "hard" trail will do that).
I was flip-flopping all over the place on driving my JKU out vs taking my trail Jeep and I'm glad I took the trail Jeep. I think I could have gotten the JK through, but it would have beat it up more than I'm comfortable with at this time. I definitely would have chosen different lines than I did with the trail Jeep. The "Jeep" just took the trail in stride wherever I pointed it. Honestly, I think the tire size was a HUGE factor. Brett and I ran the biggest tires and had the least issues with the trails. I'm running 38" Kevlars and he's running 39" Iroks. I think EVERYONE else was running 35" tires with manual transmissions. I KNOW I was the only one with a slushbox and that made some parts of the trail pretty stinking easy, to be honest.
I didn't kill any parts on my one ton rig, but it's going to kill some parts if I spent, say 10 days on the trail? Dumb stuff like leaf springs, trans mounts or the like. I doubt I'd kill axles, but smaller things are going to get a workout. More gas pedal will kill more parts. Whatever's weak in your drivetrain will bust.