We just returned from Indonesia and visited Yogyakarta - we were fortunate to arrange a tour with Gagat Handoyo.  He helped design a wonderfully flexible and informative few days and it all began when he and his driver picked us up (there were 8 of us) at the airport.  the highlights were the Prambanan, the Ramayana Ballet and the Palace.  He selected wonderful restaurants and everything was so well planned.  He is informed, easy to speak to and listened when we wanted to change things.  We will definitley call him again when we return.  Please reach out to Gagat if you plan a trip to Java - Yogyakarta.  It made the entire experience very special and memorable.