Trail to El Salto Del Nogal. From Tapalpa, ask for road to town of Atauco or Soyotlan de Los Reyes and then hike for a half-day. Also check out San Miguel De Allende. And also the Casa de Sierra Nevada (52) 415-27040
Note: Prior to 1997, the topographic maps developed by the federal government used the NAD27 CONUS datum. Starting in 1998, the government transitioned to the ITRF92 datum (some maps show both datum), which is pretty much identical to the WGS84 datum.
Overall, La Sierra Del Tigre is the 1st most popular hiking trail of all 11 hikes in Mexico.