travel south japan without booking

Hi all,

I'm planning to travel to south Japan next month, to the farest Hakata and Miyazaki (I'll go from Tokyo). First drop will be Nagoya. My stay will be free to explore places, and I probably will stay over in the major cities (Osaka, Kyoto, Fukuoka, etc).

My question is, is it possible/ convenient to go travel without booking accommodation in advance? I plan to stay at youth hostel to save some money. Or even bring sleeping bag.

And is 18 kippu of any good in this kind of travel?

Any share of experience will be appreciated. Thanks!

My question is, is it possible/ convenient to go travel without booking accommodation in advance?

Possible yes, especially during the low season, which February belongs to. Convenient no, unless you need to be flexible. I find it a pain making hotel reservations while you are traveling. If you intend to do so, nevertheless, I recommend to bring good lists of cheap hotels/hostels of every place you plan to visit and call the day before staying there.

Of course, there is always the risk that your intended hostel or budget range is full.

Don't overnight in public. It is not acceptable in Japan (and cold in February).

And is 18 kippu of any good in this kind of travel?

Getting from Tokyo to Kyushu will take you two days with the Seishun 18 Kippu with lots of train transfers along the way. I don't think it is a convenient way to travel. Domestic flights can be an amazingly cheap alternative at times:
http://www.japan-guide.com/e/e2364.html