Similarly to Els and Ian I ended up visiting both Cuernavaca and Tepoztlán. I say ended up as my original plan was to only visit Cuernavaca. Cuernavaca has the benefit that you are passing through the town in any case when travelling from Mexico City to Xochicalco by bus. So it's really quite a simple and quick visit.

However, Cuernavaca is underwhelming as a site. Of the inscribed monasteries, Cuernavaca is the one which was redone and remodeled the most over the centuries. So much so that little original 16th century constructions remain. The oldest part is the open chapel, the Capilla abierta. And frankly I barely noticed it.

So after I had done my loop through Mexico on my last day in Mexico I traveled to Tepoztlán to fill the gap. Tepoztlán is the superior site with an actual monastery and pretty murals being preserved. I really enjoyed my visit and if you were to visit one of the two, I would go for Tepoztlán.

Getting There

Both Tepoztlán and Cuernavaca are connected by direct express bus from Mexico City. Cuernavaca has multiple bus terminal while the bus stop in Tepoztlán is on the main road on the outskirts of the town.

While You Are There

From Cuernavaca you can connect to Xochicalco by bus. Cuernavaca also boasts a nice old town, specifically the market square with the home of Cortes. Tepoztlán is a fairly sleepy town. The main attraction is the pyramid towering the town on a cliff. I do recommend the hike up for the views and the experience.

Trivia

The state of Morelos was the home state of Emiliano Zapata, one key figure of the Mexican revolution. If you are interested in this, I recommend the Revolutions podcast.

As pointed out by Solivagant the reference to Popocatepetl makes very little sense.