Hello there , I was at Indonesia last year in September for a week. I will tell you how to travel alone in Mount Bromo, It is very easy.
1. Find a flight to Surabaya. From Thailand, there is no direct flight to get there. You need to stop Kuala Lumpur or Singapore before. For my trip, I had to stay at Singapore airport for the night before my flight to Surabaya in the next morning.
2. When you are arrived to the Surabaya Airport, you will see, after the gates, Shuttle bus counter. This shuttle bus will drive you to Purabaya station (Bus station)
3. When you arrive at Purabaya station. Many people will come to speak with you fast and loud. It is very noisy. Just ignore them and get out of there. Try to find a signs “Probolinggo” and take the bus to Probolinggo station (30.000 Rp)
4. When you arrive at Probolinggo station. You will see minibus to Cemoro Lawang.(also Cemara Lawang) This minibus has to wait 15 persons before starting to go there. (35.000 Rp)
If you don’t want to wait, ou need to pay more. The price is negotiable.
5. The bus will stop T-junction at Cemoro Lawang. Then you can find the place you want to stay. I stayed at Yog homestay, it is near to T-junction (Shared bathroom and good wifi for 150.000 Rp per night) and Cemara Indah (Starts 350.000 Rp per night and there is hot shower, include breakfast but the wifi is only available at restaurant)
6. At Cemara Indah restaurant, food prices around 43.000 Rp per dish
7. Usually you have to pay fee entrance for Mount Bromo but I have another way to recommend you. You don’t need to pay and it is not dangerous. This way is near Cemara Indah hotel restaurant. When you arrive there, you will see it.
8. Do not forget to go to Penanjakan view point to catch the sunrise over Mount Bromo.
9. The last minibus from Cemoro Lawang at 9.30 am but when I was there I have to wait until 1 pm because it is not full. (15 people)