I don't know if you've heard about them, but you may want to consider a Ju-hachi Kippu instead of a rail pass. It's far less expensive... it was 11,500 yen for 5 all day passes.
The nice thing about the Ju-hachi Kippu is that you don't need to use the tickets consecutively. You can use 1 all day pass, get to where you're going, look around for a few days, and then use another pass to either keep going or return. The Rail pass, on the other hand, is a set number of consecutive days, meaning if you spend a day or 2 looking around in a location, they are wasted from the pass. Also, you can buy the tickets from any train station in Japan, while the Rail Pass can only be bought overseas.
The drawbacks of the Ju-hachi kippu is that you can only ride local trains and a few Express trains if they are the only train that travels that route. You can't ride most other Express trains, or the bullet train. Also, they only sell the tickets during the Japanese holiday seasons, and that season's tickets expire when the season is over, so you'll have to watch the dates on them.
Here's more info on them...
Seishun Juhachi Kippu (Seishun 18 Kippu),
Japanese Railways Page
I used them all the time, it's far cheaper and more versatile than the Rail Pass, if you have the time to take local trains instead of the bullet trains and express trains.