Glad to read you're considering Real de Catorce. Not cheap but worth blowing the budget for a day or two.
I expect you'll surprise me with how cheaply you can do it.
"You don't take photos for yourself, you take them for the old man you will become - if you are lucky." - Falang
"As long as there's a horizon and I can see it, then I want to know what's there, mentally, physically and visually" - rtwpaul