Tokyo - Osaka - open to suggestions

Hi,
A 7 or 14 day pass would not pay off for a one way itinerary you are suggesting.
There are other ways to travel cheaply though such as from Narita there is the ¥1000 yen bus, and to get around the city there is a 2 or 3 day subway pass. For day trips near Tokyo, a Tokyo Wide Pass, and there are many good places to see, like Nikko, Izu, Kusatsu, Karuizawa, Takao, and so on.
Since you are already seeing Tokyo, you can largely skip Osaka during the day. After the temples of Kyoto close down around 5PM, you can zip over to Osaka for the evening. At night the city comes alive and has some great places to see, such as Dotonbori, plus the night views from the Umeda Sky Bldg, and Abeno Harukas Bldg are wonderful.
On another evening, you could also go and see Kobe.
Kyoto is worth several days, but don't skip Nara either. In Nara, the Todaiji Great Buddha is an extraordinary place, as well as many other historic temples, shrines and gardens in the area.

If you are traveling with your boyfriend, you might try staying at some love hotels. They are all over the country, and can be very memorable.

Good luck.