Crash site is near Iturbide Neuvo Leon - more or less a direct line from Monterey to Toluca. Guadalajara doesn't enter the picture.
iturbide nuevo leon - Google Maps
Rugged terrain, but with only sporadic peaks reaching 10,000 ft/3300 m. That seems pretty low for a Lear after 10 minutes of climb, unless there was some other factor that kept them unusually low (pressurization failure, ATC restriction).
But this report does mention they had only "reached 11,000 feet..."
Latin music star Jenni Rivera believed dead in plane crash - latimes.com