Note: When we did Cuatro peak, we started out going up Trinchera first and then following the central ridge south to the summit of Cuatro, passing over several other minor, unranked sub peaks along the way. The one way and overall mileage for Cuatro is measured from the summit of Trinchera, as is the elevation gain. If doing both summits, combine the one way mileage and elevation gain for Trinchera along with the figures for Cuatro to obtain an overall mileage and elevation gain estimate. This route description begins from the summit of Trinchera Peak. Consult that peak for both "Approach" and route.
From the summit of Trinchera Peak, walk south losing over 300 feet in elevation and cross over a minor bump of 13,250 ft., then follow the ridge SE over "Leaning North Peak," a rather minor bump. Head south still following the central ridge, dropping to a saddle and then gaining over 400 feet to Pt.13,203, aka: "Leaning South Peak." Once again, lose over 200 feet in elevation to another saddle as you keep walking south. Skirt or walk directly over Pt.13,134, drop to the next saddle and then make the final 500 foot ascent to Cuatro Peak. Almost all of this terrain is on easy-going tundra with embedded rocks and some occasional exposed rocky rubble. There are no difficulties to overcome. Enjoy the vistas. The next point south, (13,335) is unranked Mt. Maxwell. South of that summit, you're off national forest land and onto private property.
To return: We hiked back north to Pt.13,203 (Leaning South Peak) and then headed directly down the well-defined east ridge dropping to 11,800 feet before exiting the ridge to the north and entering a large basin. There was some talus to work our way through with some extra ups and downs as we worked our way north into the next basin labeled as the "North Fork Purgatoire River." Staying fairly high to avoid willows as best we could, we came out within a quarter mile of our vehicle park at just above 11,600 feet on the access 4WD road. Be prepared for some willow-bashing on this last section. It is mainly the difficulties of the return that compels us to rate Cuatro as Class 2 verses the Class 1 rating for Trinchera.