Trip during Febuary

Hi everyone,
My girlfriend and I have planned a trip to japan from the 30th of January till the 16th of Febuary.
We arrive in Osaka and plan to stay the night there.
From there we travel to tokyo and stay an extra night or two before we start our INTREPID tour which takes us through Tokyo, Nikko, Hakone, Takayama, Hiroshima and then finally Kyoto.
After Kyoto we stay there for one extra night before getting the train to osaka to the airport.

I have a few questions that any help would really help.

- Since we're staying for only a little more that 14 days, should we get the 21 day rail pass? our intrepid tour says we NEED a 14 day, but would it be cheaper to get the 21 day or get the 14 and pay for a few extra trips?
- While we're in Tokyo, we want to definately visit Harajuku. Any tips?
- Since we're coming from Australia, what is the best way to carry money around? Should we exchange money in our country or once we're in japan? Should we carry mostly cash with us, travellers cheques, or a pre-paid credit card? Do normal Austrlian ATM cards work over there?
- Whats the nightlife like over there? Is it 18+ or 21+ and how strict are they on this?
- Should we bring a language translation book or do most people understand english?

Any help would be greatly appreciated =]

Since we're staying for only a little more that 14 days, should we get the 21 day rail pass?

If you can cover all your long distance trips by a 14-day pass, it is recommended over a 21-day pass.

While we're in Tokyo, we want to definately visit Harajuku. Any tips?

About Harajuku and the rest of Tokyo:
http://www.japan-guide.com/e/e2164.html

Whats the nightlife like over there? Is it 18+ or 21+

It is 20+ for alcohol and cigarettes.

- Since we're coming from Australia, what is the best way to carry money around? Should we exchange money in our country or once we're in japan? Should we carry mostly cash with us, travellers cheques, or a pre-paid credit card? Do normal Austrlian ATM cards work over there?
http://www.japan-guide.com/e/e2208.html

- Should we bring a language translation book or do most people understand english?
No. Most Japanese do not speak it. But that wont be a problem for foreign travellers as long as they travel in the popular tourist destinations.

Thankyou for your help Uji and Jtraveller.

Our intrepid tour doesnt cover Osaka and very limited Tokyo. So i have a few more questions:

- While in Tokyo we plan to visit the Flea markets. Any advice on how to go about this and when they will be on during late january?

- When we're visiting Harajuku, it will probably be mid-week during late january. Will we be able to see any cosplay since teenagers will probably be on school holidays?

- Ive read the japan-guide Osaka City Travel Guide but since we only have limited time in osaka i was wondering whats the best places to visit. We will definately visit the aquarium, but will that take up a whole day?

- While in Tokyo we plan to visit the Flea markets. Any advice on how to go about this and when they will be on during late january?
days?
http://www.paperlantern.net/fleamarket/

- Ive read the japan-guide Osaka City Travel Guide but since we only have limited time in osaka i was wondering whats the best places to visit. We will definately visit the aquarium, but will that take up a whole day?
I guess you will like Unversal Studio Japan.:) or
http://www.jnto.go.jp/eng/location/regional/osaka/index.html