You can get to the base of the climb via one of two ways... either from the town of Rio Frio... a standard route, but one I know nothing of or from San Pablo (near Texcoco) and by following the aqueduct up to the valley Tealpon shares with Tlaloc known to locals as 'manantiales' or spring in English. From there Telapon is the more southerly of the two big peaks, with a more tapered pyramidal summit and lies due east along the valley floor.
While Telapon isn't vsible when you first reach Manantiales if one hikes out to where the valley opens up (towards Tlaloc) and continues moving in an easterly direction, along the valley you can't miss it, it is too big to miss.
The path of least resistance (which was what I was looking for when I climbed Telapon due to time constraints) lies to the east of the Bluffs which dominate the little section of the valley that I have named the Valley of Telapon (no stroke of genius here). From here I proceded upwards slightly southwest until I emerged into a gentle section of the forest. From there work up a steep section keeping gradually southeast, (I passed a recent 'burn'-guidepost) and keep on this track until you emerge either on the summit ridge proper or slightly to the west.
From the summit, the approach is straighforward though I would keep to the west as their is a nice ridge of rock which is much more accomodating then the scree.
If you emerge to the west I would suggest downclimbing eastwards and then working your way up the rocky summit approach until you are on the main ridge with the gendarme to the west and then its a scramble to the top.
Round trip the hike from Manantiales should take 2-4 hours and is about 7-8km, with an elevation gain of 700 meters or so.
Sturdy boots maybe an alpenstock or poles, lots of sun screen and water and all weather gear as the weather can change without warning in a matter of minutes.
note: If you run low on water, the water from the aquaduct is pretty dependable (surprisingly enough)... with only iodine I used it and came away with no side effects. The 'revenge' was nowhere in sight. The best place is just after you emerge into the valley proper and the stream goes underground.
If you have information about this route that doesn't pertain to any of the other sections, please add it here.