El Flaco is dead on. The only thing worth adding is that if you go play at Cibeque, keep your eye on the sky. The road home is easily washed out by rain.
The trip to the ledges isn't too bad, but don't mess with the locals. No means no there, and you will loose all of your gear - both on you and in your car - if you don't respect their property. Stay river left on the hike back - bring shoes & be prepared to paddle some flat sections upstream.
There is a downstream alternative, but its not easy. Get a good map of AZ. If you are traveling form the west (Phoenix), you will find a really small park / town just before you start to descend into the canyon. There is a road that branches off to the left (towards a small lake). Your map should lead you down some steep, dirt switch-backs and onto a plateau about 100 feet above the river (about one hour from pavement). There is a sketchy-little foot path that starts on the river-side of the plateau and heads downstream. It will bring you to the river, and you can then hike upstream to the ledges less than a half-mile. I did it once & swore I would never drive my jeep back there again, but it is all you get for P&P in AZ