Here is a brief response to a very deep subject. First, it wasn't a club ride, it was 3 of us who happen to be members of the club. We went as part of a group that goes there now twice a year. For the weekend there was about 44 riders, then after the weekend there was about 20 of us left.
The ride wasn't to Monterrey but into the Sierra Madre mountains south. I'll save the details for the ride reports you can read at the Two Wheel Texans website:
http://twtex.com/forums/showthread.php?p=1577869#post1577869
Some thoughts about riding in Mexico. If you don't speak Spanish you need to go with someone who does. You can by on a little Spanish but if you have any issues you might have problems getting help or understanding people. I have a little Spanish and have ridden (or driven my car) in Mexico half a dozen times and I would not go solo. Is it possible but the rules are all different there so if anything happens what will you do? A phrase I heard once says "Mexico is the land of ultimate personal accountability." Be prepared.
All that being said it is an absolutely beautiful country with extraordinarily friendly and generous people. Visiting really is addictive! You can absolutely take a road bike and the highways are scenic and twisty.
Be careful not to overrun your braking distance as there will be potholes, rocks, dogs, donkeys, and broken down pickup trucks around the next corner.
Is it safe? There are cartels and banditos and bad things happen all the time. But imagine a Mexican thinking about visiting the US and watching our news (mass shootings, politics, car accidents). He would think it is too dangerous to come here! That's Mexico!
Bottom line: read and research. For your first visit go with someone who is more experienced. Lots to learn but that is the adventure. If you just want pretty scenery go to Colorado.
In my humble opinion...