This is an itinerary for Java suggested by a driver I've been in touch with:

Aug 22 fly to Surabaya – transfer 3 hours to Bromo – Stay LAVA VIEW BROMO.
Aug 23 Bromo Adventure – Malang – Stay at VILLA DEDAUN BATU MALANG.
Aug 24 Malang Tour Water Fall – Drive to Blitar – Stay TUGU HOTEL BLITAR.
Aug 25 Blitar – Anak Kelud Volcano – Stay RUMAH TURI SOLO.
Aug 26 Solo – Drive to Borobudur – Stay MANOHARA BOROBUDUR.
Aug 27 Borobudur Tour – Dieng Plateau – Stay BERG VIEW MAGELANG.
Aug 28 Magelang – Yogyakarta City Tour – Prambanan Temple – Stay RUMAH PALAGAN
Aug 29 Free and Easy Yogyakarta – RUMAH PALAGAN
Aug 30 Airport transfer – afternoon flight – connect to Jakarta – overseas

Leaving out going to Bromo, does this sound doable? I have 2 more days, Aug. 31 and Sept. 1 since this was suggested. It would all be done by car.
The hotels listed were his suggestions. I may go with other ones that I find on my own. I hear the Phoenix in Yogyakarta is a nice hotel.