This route description begins from the end of the Endlich Mesa trail approach which terminates at the NE end of City Reservoir #1 at our suggested camp location. From that campsite, follow trail #534 north as it climbs steeply up the valley toward Lake Marie. Shortly before arriving at that lake, the trail switchbacks to the south, rounds a ridge to the west, then climbs on up onto Silver Mesa. Once atop the mesa, you'll be above timberline. After a while, the trail will tend to fade amidst granite outcrops and was identified at times, only by cairns. We found it easy to wander off it, but would usually find it again. The trial heads mostly north and takes you by the Pittsburg Mine. From there, walk another 3/4 mile NNW to where you can easily overlook the basin south of Aztec. In the lush, green grass below, you may have the opportunity to spot a herd of elk.
From this vantage point, south of the peak, it ma be difficult to determine which "bump" is Aztec Mtn. A GPS could be useful in doing so. We decided the easiest thing to do was to lose about 300 feet I elevation and angle NNW, then west into the basin below and cross the head of it over to a saddle at 12,860 ft. This will be the saddle between Aztec and Mt. Kennedy to the west. Follow mostly grassy slopes to that saddle and if your seasonal timing is right, enjoy some beautiful, blue columbine along the way. At the saddle, you may want to first turn left and make the quick and easy trip up along the ridge to bag Mt. Kennedy. If not, turn right (east) and walk up to the Aztec summit. There will be a minor false summit to bypass and a finish on scree-like rock. The hike from the lakeside campsite may take up to 4 hours.
The most redeeming aspect of climbing Aztec Mountain is the bird's-eye view of Chicago Basin and the three 14ers. The view is quite impressive. From the summit, either return as you came, or head down the east ridge and decide if you want to return to camp or head on for Mount Valois, which could also include a trip over Bullion Mtn. and Florida Mtn, both unranked summits.
Links to other information, routes & trip reports for this peak that may be helpful.