Japan - July 17 to August 2
USA - September 21 to October 11 (maybe)
Osaka - July 17 to July 21 (plus Kobe, Hiroshima and Nara)
Kyoto - July 22 to July 23
Tokyo - July 24 to July 28 (plus Yokohama)
Naeba - July 29 to August 2 (Fuji Rock Festival)
Flights - booked
Hotels - someone else
Trains - 14 day Japan Rail pass
Festival - booked
Only thing that remains is to research and fill in what to do each day. Also Japan is kinda expensive, particularly the trains.