Yes Samurai, your idea is good!
Its' very difficult to calculate every journey to understand what's the best choise.
If I have well understand:
for all days that I will stay in Tokyo, I can buy a singol all ticekts (it's ok for subway and buses).
Can I go to Kamakura and Disneyland with this type of ticket?
Then, when I will go to Takayama to Kyoto, I use a JRP (if is it cheap) that I can use it for 7 days.
After, the last day, you recommend me to leave to Osaka.
many thanks!