Hey Arte i been around that Elias Calles Dam too, and around there like 10-15 km away is a place called "Boca de Tunel" is marked on a map that you showed us, i dont know the elevation of that place but is a W H O L E different ecosystem, is not like semi-arid dried-thorn bushes, is not that dusty in fact you ride on a big pinkish rock terrain; and they have some tracks for mountain bikes, this poleas things from one mount to another in few words a very eco-turistic place. When you drive around there you will fall in love,
Boca de Tunel is around those mountains in the back
if you go one day take travel over there, it has became my favorite spot in aguascalientes
By the way, se le extraña en el foro touareg hermano!