Absolutely! A trip to Surabaya, Malang, Bromo, and Ijen promises a diverse and enriching experience. Here are some travel tips for you:

Best Time to Visit:
The best time to visit these places is during the dry season (May to September), when the weather is pleasant and ideal for sightseeing and outdoor activities.

Route and Accessibility:
You can start your journey in Surabaya and then move on to Malang, Bromo, and finally Ijen. Direct flights to Surabaya are available from various international locations. Local transportation like buses, trains or cabs are available to get around.

Altitude and Acclimatization:
Bromo and Ijen are both volcanoes and a bit high in altitude. It is advisable to take a day to acclimatize to the altitude, particularly before trekking to the mountain peaks.

Accommodation and Booking:
Good accommodation options are available in all these places. Try to book your accommodations well in advance, especially during peak travel seasons to avoid the price surge and unavailability of rooms.

Clothing and Essentials:
Carry light clothing but also include warm jackets or sweaters as it can be cooler especially in Bromo and Ijen during the early morning ascend. Good trekking shoes are a must if you are planning to trek to the Ijen volcano.

Health and Safety:
Carry necessary medications and travel/adventure insurance for emergencies. Stay adequately hydrated and use sunscreen generously during treks to avoid sunburns.

Local Etiquette and Respect:
Indonesia is a multicultural country. Respect local traditions and dress modestly. Defer to local customs where necessary, and it may also be good to learn a few basic Indonesian phrases.

Lastly, always remember to enjoy the local food, the views, and the hospitality of the people. Enjoy your trip!