Start from the Emmaline Lake Trailhead and climb to the top of Mummy Pass. (For directions to Emmaline Lake Trailhead refer to the "Getting There" section.)
From the top of Mummy Pass, continue down the trail past the small lake. A couple of hundred yards past the small lake veer off to your left through the trees and descend into the valley between Mummy Pass and Icefield Pass. Cross the creek in the valley and then contour along the small hills, steadily gaining altitude as you near Icefield Pass.
When you reach the top of Icefield Pass, make sure to look down toward Lake Louise, as the view is very pretty. After you take in the view of Lake Louise, head south up the valley with the ice field. Stay on the left side (east side) of the ice field and steadily gain elevation as you climb up the valley. As you near the top of the ice field, you’ll see what looks like a peak to the east. This is not the summit of Rowe Peak! Climb toward what looks like the saddle between this unnamed peak and the top of the valley. When you reach this apparent saddle you’ll come to a pretty steep rock face that drops down into the North Fork of the Big Thompson. From this spot, you’ll be able to see Hagues Peak and the summit of Rowe Peak. Climb along the edge of this cliff until you can’t climb any higher and you’re there. Up until the point where you could see Hagues Peak, the hike has been through tundra. The last section is up talus. It’s very comparable to the summit of Mount Bierstadt. From the summit, enjoy the spectacular view of Hagues Peak and Rowe Glacier.
This is a very long hike. When I did it, I left the trailhead at 7:15am, reached the summit at 1:10pm, and returned to the trailhead at 7:00pm. I was experiencing some altitude sickness (nausea and headache) from Icefield Pass onward, but even if I’d felt 100% it still would have been a rough day.
It would be nice to break this hike into a two-day trip, however that's not really feasible. Camping is not allowed anywhere near the route once you get into Rocky Mountain National Park (i.e. after Mummy Pass). Camping on the Comanche Peak Wilderness side of the pass isn't very attractive because there are no sources of water--I hate packing all my water.
I climbed this peak in October and needed no special gear--just the usual warm cloths for hiking in the mountains. If you were going to do this hike in the winter or spring, you still wouldn't need special gear because the hike is not technical. All you'd need would be snowshoes or cross-country skis to keep you on top of the snow.