Help with first Japan trip (August)

First of all I would like to thank anyone that put their time into helping me.

I'm planning on going to Japan this August, and yeah I know I don't have a lot of time. I would like to go for 21 days, since I'll be buying a 21 day rail pass. I want to experience some Onsen, nightlife, and major cultural sites. I've used the itinerary feature on this site, but it seems to list mostly cultural sites. I would also like to know if it would be better to leave the Onsen experience for another time since it will be summer there.

I'm currently looking at different travel guides and would like to know which is better: Frommer, Lonely Planet, or Fodor?

By the way I want an adventure, not a nice resort type of trip. Though I would like to stay in some nice Ryokans. Most of my stay will be in hostels. I believe I can meet some people with same interests there and make some friends.

Oh and if anyone would like to go together, lets do it hehe.

Thanks again for your time,

Marcelo

I recommend to use this website and guide books to research and pick a selection of destinations that sound most interesting to you:
http://www.japan-guide.com/e/e623a.html

As for guide books, it is personal preference. If you like to have detailed practical information, I recommend Lonely Planet for low-budget travelers and Fodor's for a higher budget.

Kusatsu Onsen is a great place for an Onsen experience.

Kyoto and Kobe are fun too. naturally there's plenty to see and do around Tokyo and the like.

Make up your schedule first, it may show you will only need a 14 day JR Pass if you stay the first days in Tokyo for example. The JR Rail Pass is money-saving for long distance travel but waste of money of municipal travel ( and in many cities worthless because of no inner-city JR trains ).

I will be going that way myself but I have a feeling we are going with the hopes of different experiences, Im going to travel by foot from Tokyo north along the coast then circle back round. If any wants to know more email me at johnunleashedpig@yahoo.com, it would be nice to have people to hang out with for a few days in different towns