Getting there is actually pretty straightforward. From Mexico City find your way to TAPO (the major bus terminal to all destinations in the south of Mexico).From TAPO find your way to Texcoco (a 45 minute bus ride) that will run about 14 pesos.
Once you arrive in Texcoco ask for the bus to San Pablo. This is another 45 minute ride and your stop is the very last one. Once you get off the bus there is a road that snakes off up into the hills which you will follow until you encounter the aqueduct. After you encounter the aqueduct follow it all the way until it goes underground. This will take anywhere from 4 to 6 hours (the distance is 11km) depending on your degree of physical fitness as Manantiales is at about 3400m or 11200 feet. From there the summit of Yeloxochtl is clearly in sight.
Once you arrive at the first open green pasture, look to the east and quite simply the highest peak you can see is Yeloxochtl. I cross this first section of Manantiales, careful to skirt around the edges as it is boggy in places and one can sink up above their knees if you aren't careful. There is a noticeable valley that the spring flows through, I hike up through here (following the stream) to the next open section of Manantiales and from there head due east to start to climb Yeloxochtl.
It should take no more than an hour to an hour and a half to reach the first summit and then an additional half hour to reach the other two (the overall altitude gain is around 500-550m). Its a relatively easy summit. You can either hike through the trees or do some class II-III scrambling on some of the bluffs and rock bands that dot her slopes... its your call. The only real difficulties can be the altitude, the heat and the sun. If you come prepared for that than it should be a very enjoyable day.
Sturdy boots, 4-5l of water, sun screen, sun glasses and trekking poles.
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