Shadman, do you think it's practical to head to Real de Catorce during this trip without extending the time past the 26th thru 29th? Do you think it best to spend the night there or can it be done enjoyably in a day?
One man's opinion: You can ride the approx. 120 miles to Real de Catorce from Galeana in a few hours (3 or so). So, technically, I think you could go there and back in a day. However, it wouldn't afford you much time to do anything else in Real, such as tour the mines, tour the smelt, walk the town, take in the sights, or enjoy the atmosphere.
My suggestion is to make it an overnight trip. Maybe ride there on Friday, stay overnight, and back to Galeana on Saturday. I suggest taking the tunnel in (main road into Real) and then taking the old road, over the mountains to the west, out.
If you want some extra adventure, leave early Friday morning, ride to General Zaragoza and take the dirt road from there that runs southwest to Doctor Arroyo (the first half of the General Zaragoza route in the MexTrek guide). From there, run pavement to Real.
On Saturday, if you again want a little extra adventure, take the old road west out of Real, back track to the dirt road towards General Zaragoza, then go north on dirt to La Escondida (the second half of the General Zaragoza route). From there it is pavement back to Galeana.