In August I took a tour from Ubud-Ijen-Bromo. It was so worth it. Although it takes some stamina waking up super early hella two nights in a row, it was hands down the best part of my trip through the region. Sofyan, Henry, and their partner tour guides were super hype and very compassionate. It’s also nice to know that your money is going straight to the people of the region and makes a big difference in their lives.
Also a few side notes, August was a great time to be in Indonesia because of the independence festivities. Bromo is not a big hike at all, except for the walk through the sand to the volcano. But for Ijen, make sure you have shoes with good treds and warm clothes.