We booked in for the Queimadas/caldeirao verde walk. In the brochure it is described as a moderate walk of 13 km. It is a beautiful walk. The guides are fun, knowledgable and very professional. We were in a group of about 20 which was a good number of people. Our fellow walkers were all good natured and fun to be with. Some needed more of a sense of humour than others! (you know who you are!)
Now for the warnings!
Wear proper walking shoes/boots - these are proper walks not to be taken lightly. Terrain can be reasonably rough, with wet areas and tunnels. Torches and walking sticks were provided.
On our walk, the end part was downhill for quite a way. Great! But for anyone with bad knees, be prepared for a pounding.
We found the walk reasonably easy, but we are used to walking. Anyone who has any problem should maybe go for an easy rated one first.