Hike wasn't too strenuous but there was rain and a lot of mud to contend with. The crater was thick with cloud when I got down inside, which led to an eerie atmosphere over the crater lake. Not a hike for the distant views, but it is impressive to hike to a lake within a volcano within a lake!
The hacienda Magdalena is a great place to stay. I formed a group with some other people staying there, and went up with a guide (5$ per person). When we got to the laguna, the clouds were just moving away, so it was good not to leave to early (we left at 7am).
The trail was quite steep and muddy in some parts. Plenty of monkeys but I wish I'd seen that snake!