According to Terry Gunn at Lees Ferry Anglers, the river is healthier now than at any time in the last decade. For a more detailed report on the Colorado River at Lee's Ferry, see the Lees Ferry Anglers fishing report which is updated weekly. Most of the other lower-elevation areas of the state offer poor trout fishing through the summer. You may have some luck at Chevelon Canyon north of Payson. There are reports there of Cicada's bringing up the Browns and Rainbows, but this won't last for long.
Some activity is reported in Canyon Creek.
Make sure you have your hiking boots for the long, rugged, snake-infested hike up the canyon. Dam reservoir southwest of Flagstaff. Try Prince Nymphs and Arizona Peacock Ladies. Fish the riffles below the top parking lot near Stewart Mountain Dam. Again, getting there early may be your most effective tactic.