The easy way: Drive up the Mt. Evans Road to Summit Lake and park. Then take a leisurely stroll along the road over to "Epaulie" and then on to Rosalie over mostly easy tundra/rock terrain.
The harder & longer but more sporting way: Drive HWY 285 and turn north on the Deer Creek Road past Harris Park to the end of the road and hike over steeper but still relatively easy terrain to Rosalie. Pre-Lidar elevation was 13,575.