N. of Madras, at the top of the hill before descending into Warm Springs, you'll see a turn off on the right. This road leads to access into the Deschutes river canyon and the Trout Creek campground and boat ramp. You'll have to map your way in from there, traveling over a mix of BLM and private lands. It's a good ways down to the river over a narrow gravel road, a bit choppy in places, but certainly no need for 4WD. Usually takes me a little less than 30 minutes with drift boat in tow once I leave the hwy.
Great spot with great fishing and swimming, I might add.http://www.rivertrails.com/Camp_Trout_Creek.html
Also, in the immediate vacinity is this: http://www.summitpost.org/trout-creek/590615
But you may wish to consider this:http://crag.org/2012/02/02/trout-creek-closed-to-climbing/
I'm unsure of the status quo.