Had a good guide and driver. Website states that it is an easy trek. But I would like oppose to that. The distance and slope was doable. But the infrastructure of the trek made it very unsafe. There were no proper pavement and railings. Esp with the activity down the Ijen crater. It is just a working mining field with no proper railings to protect people should they slip and fall. It was so crowded with people that I was afraid someone would slip and grab me down with them. As such, I gave up halfway down the crater. Safety above all always. On top of that, the sulfur gas made it so hard to breathe and see. My advise to everyone is to skip the crater activity to see the blue fire and just head up to the peak to catch the sun rise.