Budget for 2 weeks?

Hello everyone,

Planning to go to japan for two weeks in september with 2 more people.
No budget for accomodation, since we’ll be sleeping at a friend’s house in Tokyo.
Flight already booked, what would be a comfortable budget for this duration?
Planning to stay in Tokyo a few days, going in the countryside (not sure where get), and also 3/4 days in okinawa! (No flight booked yet though)
I was thinking maybe between 340 000 and 500 000¥/pers? (I don’t want to think to much about budget during holidays)

Apologies for my english, and thank you!