While climbing up to Pico del Fraile when visiting Nevado de Toluca (also known as Xinantécatl), the idea of running from the heart of Toluca all the way to the peak came to me. Nevado de Toluca is the fourth highest formation in Mexico and reaches up to 15,387ft / 4645 m. It seems to be a very popular place for bicyclists to ride up to from Toluca. I also saw a handful of runners at the entrance and even witnessed a 50k race at the bottom of the volcano. 

The below text has been taken from Wikipedia: https://en.wikipedia.org/wiki/Saint_Illtyd%27s_Walk

1. The walk was mapped out (over pre-existing footpaths) in 1994, to celebrate the 10th anniversary of the Llanelli Ramblers. Colin Davies, who devised the route, authored a guidebook the same year detailing the walk.

This route starts at the Sacred Rim trail head and ends at the famous Photographers point. Photographers point looks out over a beautiful canyon as a reward for your journey. The journey itself is something to enjoy as well, immersed in the pines and running amongst moose and other wildlife. The trails are not too technical and have an amazing flow. This should be a must do if in the area.