More than half of the Indo population lives on Java island and the capital Jakarta is home to many universities and private institutions. Many of the vacancies that become available will be in or near the city.
While Jakarta may not be what you picture in your Indo dream, as the greenery in the area is quite limited, it still has plenty to offer in terms of night life, restaurants, shopping and museums. There is certainly always something to do. There is also an airport with affordable short hopper flights to other islands, so weekend trips are doable.
Sumatra is catching up with Java in popularity and the number of opportunities for new teachers seems to be rising steadily with Medan attracting the most new recruits.
Sumatra is known for its wildlife and is a major go-to for adventure lovers and trekkers. It is one of the very few places in the world to see orangutans, so also brings in just about anybody who is fascinated with primatology or rare species. If you want proximity to real jungle life, it is a great option.
Probably, when you do fantasize about living in Indonesia tropical Bali is the fantasy. The island is the tourist mecca of Indonesia, due to the almost indulgent amount of natural beauty.
It has everything: jungles, volcanoes, beaches, and quaint towns.
Jobs in Bali are few and sometimes far between, but do come up. If you have good experience and a TEFL qualification it may be worth it to wait for a position, or to make connections on the island who can relay information if they hear of any new openings.