Cheap guesthouses will run 50,000 yen/month (maybe plus 25,000 refundable deposit).
Food will probably run 30,000-40,000 yen/month.
Local transportation may be 25,000 yen/month.
I'd say if this is all you have to pay for, and the course you want is already taken into account with other money, then 250,000 in pocket is ok, but just barely for 2 months. Many guesthouses will run 80,000.