You have to pick four preferred months, so I picked November-February, but the colors will be the last week of November or the first week of December. You might get some flow for the winter monsoon in January or February. While you can do this hike any time of the year, in the late fall you will want to start no earlier than 0730, so that you have decent light for photographing the trees. Luckily, it appears the satellite passed over in late fall, so if you view the official route in sat view, you will see where the colors are concentrated.Warning:
There's a fair bit of garbage in the first half mile, which is certain to contain nails. Also, there's a number of popular firing ranges in the area, one of which I've marked on the route.
Upper Arnett Creek, which you start on, will probably be bone dry. The unnamed canyon in the middle has many, many pools; I have observed flow in it on a previous occasion. Telegraph Canyon will be mostly dry, but may have a pool or slight trickle. Lower Arnett Canyon, just after the Finger Rock, was quite muddy in the creek bottom, indicating heavy prior flow.
Find your way through the garbage to Arnett Creek, and start walking south.
: Near the quarry, you will encounter the first colors, which you will pass through the arched middle of.
: At the cattle grate, you will encounter the second set of colors, which you will pass to the side of. (This puts the trees to your left, and the sun to your front, whereas heading down the middle of the trees will put the sun in front of you, making for more difficult photos.) At the end of the colors, turn west into Wood Canyon, in which there may be a few colorful trees.
: Exit the creek bottom, heading up slope, through the emerald rocks, along a foot path.
: At the top of the saddle, where the foot path continues west towards Filaria Spring, turn north into the unnamed canyon. The canyon is a mile-long series of slick rock, light vegetation and pools. It may very well be flowing. Picking your way down canyon is not difficult.
: The third set of colors, which I described last year as looking like well-aged Wisconsin cheddar (if you catch them at their peak). Afterwards, turn east on FR 4 for a few feet, turning north just past the knob, beginning your climb to the rim above lower Arnett Creek.
: As you follow the rim, you will pass the first big cairn, on your way to the overlook at 4.50 miles. After the overlook, continue to follow the rim west along Telegraph Canyon, observing colors along the canyon's bottom.
: Duck under the barbwire fence, then pass by the second big cairn at 5.25 miles.
: Follow the access path into Telegraph Canyon. It is a mild descent of only 80 feet. At the bottom turn east along the established path. Although the brush can be quite dense, stop often, scanning left, right and backwards, to spot further colors.
: The fifth set of colors will be near the Finger Rock, at the confluence of Telegraph Canyon and Arnett Creek. Find the right angle, and you will be able to frame the Finger Rock in golden leaves. Turn east along Arnett Creek. The creek bottom may be quite muddy, but there is a path to the side. Lighting may be challenging due to the colors being between you and the sun, plus the cliff being between you and the sun. Contrast could be severe. The highlight is the only red tree I spotted, at 7.00 miles, just before the quarry. After the red tree, follow the dirt roads back to the trailhead.