We’ll be in Mexico City for 8 nights, arriving on a Saturday. Since we have a full week to play with, I was wondering which day would be the best day to visit Teotihuacan. Some travel sites recommend going on Monday since that’s the day most museums are closed, but I would think that’s the day everyone goes for that reason. So are we better off going on another day that week or would Monday be a safe bet.

I would say go on the day that best fits the rest of whatever schedule you might arrange. Except Sundays, when entrance is free for citizens. At least I'm pretty sure it's free for locals then. It's a massive site that can handle significant crowds. You should do lunch at La Gruta.

Thanks, baldone. I’ve found a driver/guide for Monday, and it works well for our schedule. I’d originally planned to do it ourselves but this presented itself and seemed like a good idea. So we’re set!