From the trailhead at 1,700', start hiking southeast up the scenic desert wash towards Castle Dome Peak. The peak is already very prominent from this distance, and will get more so as you get closer. The wash is sandy in places, so your travel will be a little slow at times. The wash is angled upwards at a gentle grade. You will gain only about 400' or so until the turnoff point. Hike up the wash for about a mile and a half until Castle Dome Peak looms large to the south. At some point, you will need to leave the wash and start climbing southeast up towards the saddle. There is no one particular location where you must leave the wash. On our February 2004 climb, we saw an arrow in the wash marking one turnoff. We left the wash here, but ended up having to traverse along the base of the cliffs in order to get to the saddle. On our January 2000 climb, we turned off a little bit further up the wash. This resulted in a more direct approach to the saddle, and is probably the better option. However, either way will work. The hiking up to this point is Class 1. You will leave the wash at about 2,100' or 2,200'.
From the wash, starting bushwhacking southeast up the rough slope to the 3,080' saddle just northeast of the mountain. Both routes we picked started off as drainages. There is no one drainage or route that you must go up. Just start heading up to the saddle. If you leave the wash early, you may have to traverse along the base of the cliffs. The climb up to the saddle is Class 2. Once at the saddle, start heading southwest up the slope towards the mountain. You will soon encounter a faint climbers path. Take this path all the way to the summit. On the way up, you will encounter a few short, steep Class 3 sections here and there, but they are not very difficult. You will also bypass a huge rock outcropping on the way up. Because the route is faint in places, we encountered one or two dead ends, but we backtracked and soon found the right way. The route is also cairned in some places. You will soon emerge onto a relatively large and flat summit, where you can enjoy the wide-open vistas of southwest Arizona.
Hiking Distance: About six miles round trip.
Elevation Gain: About 2,100'.
When you leave the vehicles, you will want to follow wash branches angling to the left. If you reach a large dry waterfall, you are too far to the right. Turn right at the rock arrow in the main wash into a small wash. After a couple hundred feet, turn left up a gully to the surrounding terrain. You should find a good climbers trail that will take you all the way to the pinnacle notch.
As Dundeel said it appears that most people are not going to the saddle west of the peak and are going up to the northerly side of the peak to where the detached pinnacle is. Once you leave the wash at the arrow, you will pick up a climbers trail that will take you to the detached pinnacle. Once at the detached pinnacle you go up near up the NE face to the top. Just find the chute with the great holds near the small saddle between the pinnacle and the NE face and go up - lots of options from there - it's all pretty easy terrain with just a touch of easy Class 3 after on the last part. More info here: http://www.peakbagger.com/peak.aspx?pid=4071