Mt. Bromo is well known smoking volcano in Java island in Indonesia. It is quite touristic spot and get there by your own is not hard.
How to get to Mt. Bromo:
Go by local bus to Probolinggo town, to Bus Terminal Bayuangga.
Near of this Bus terminal, there is a Mini-Van stop (GPS: -7.767147, 113.173159). There are tourist mini-vans to Cemoro Lawang village for Mt. Bromo. Drivers are waiting for tourists to fully occupied the mini-van. There are no time table. Mini-vans are operating during the day and waiting for tourists. I am not sure about low season.
Go to Cemoro Lawang village to the end station. There are many homestays and guesthouses for tourists. It is possible to find a cheap one.
From Cemoro Lawang village is just few kilometers to Mt. Bromo.
I recommend you to walk to Mt. Bromo on the top. Do not take a taxi car (jeep) or motorbike, it is not so far. If you take a car, you have to pay entrance car fee.
Walk on the Mt. Bromo during the day. Stay at Cemoro Lawang village at least 2 nights. My recommendation is to not go watching the sunrise like most of the tourists. I did it and regret it, because it is nonsense. The sunrise is not so interesting, not even over the volcano and waking up at 2am and night-walking was really crazy. Sunrise are watching only naive western tourists 🙂 It is quite good business to drive tourists for sunrise. Walk during the day like local Indonesian tourists.
The same mini-vans will drive you in the morning (till 10 am) back from Cemoro Lawang to Probolinggo Bus Terminal Bayuangga. From there, you can take a direct bus to Surabaya, or direct bus to Bali.