If you are planning to visit Mt Bromo and Ijen Crater in East Java, there are for info that you may need to know:
Prepare with warm clothing. For people used to live in cold weather maybe the temperature will not be a problem, but no harm preparing this. Make sure you bring socks, hat to prevent from wind, scarfs, few Indonesian wear gloves when visiting Bromo. And even if you dont bring jacket you can rent jacket for Rp.20.000, and buy hat or scarf at Bromo area. Do not fporget to bargain.
Flashlight will be helpful for you to climb Mt Penanjakan, if there is no moonlight, it could be hard to see your way. If you go with tour operator, usually guide is already prepared with flashlight and mask.
After Bromo eruption from Nov 2010 to May 2011, Bromo was in alert status. So people could only see MT Bromo from radius 2 KM. And because of the erossion of road from Cemoro Lawang to Mt Penanjakan, if you are from Cemoro Lawang you will have to trekk from Cemoro Lawang to Mt Penanjakan for about 1 hour to get to the summit of Mt Penanjakan, as Jeep that usually transport tourist from Cemoro Lawang to Penanjakan can not pass the broken road. So depart at 03.00 from your hotel to climb Mt Penanjakan. From hotel you can take jeep or motorbike taxi or walk to the foot of Mt penanjakan. If you are from Tosari, pasurian Regency, the road to Mt Penanjakan is still accesible by jeep but jeep can not drive to sea of sand and Mt Bromo, and you can take ojek instead to go to Mt Bromo.
When visiting Mt Bromo, you can also take excursion to the wispering savanna by driving Jeep. If you like to see more of local people (tenggerese) activities, or wander a bit, do it after arriving in Cemoro Lawang, you will make nice shots to bring home. If you feel you are just interested to see sunrise and see the crater of Mt Bromo, you can depart midnight from Surabaya.
Blue Lava of Ijen crater can be seen when it is still dark, you should depart at 1 or 2 am from hotel for this purpose.
Prepare yourself with mask when visiting IJen crater, wet your mask with water will better filter the sulphure in the air.
And sure you should wear sneakers!
Have nice trip to Bromo and Ijen guys!