Yes, better to travel through slowly and arrange your transport at each stage, yourself. Tours like that may sound good and an easy way to 'tick off' another sight, but it's true, not pleasant. Covering all those km in a fast and cramped minibus IS dangerous. Take the train wherever possible. I would always opt for a large public bus over a hurrying tour bus, more safe. Use your guide book and choose your hotel when you get there, after you've checked it out, and stay...stay a couple of nights at Bromo, slow down, enjoy the place...and make all the long hours of travel worth it.