Hi,
If you use the JR Pass to either go to or from Narita Airport on the Narita Express, and then also Tokyo-Kyoto-Tokyo, then buying the 7 day pass makes sense. For the time you can't use the pass for Narita, you might take a 1000 yen bus. Or if you mean go straight from Disneyland to Narita Airport, then check their access webpage.
In Kyoto you could spend weeks there and not see everything. The three best sights though are the Kinkakuji Temple, Kiyomizudera Temple, and Fushimi Inari Shrine. Fushimi is the most time consuming; you could spend a couple of hours to over half a day if you want to romp over all the trails.
And the Otagi Nenbutsuji is one of the most humorous and whimsical places you could visit in Japan - well worth visiting, even for kids.
Nara is often neglected by some tourists, which is a shame. Missing the Todaiji in Nara is like going to India and skipping the Taj Mahal. Nara Park has a lot of great places. A few other great places missed out even by those who go to Nara though are the Isuien and Yoshikien Gardens. They are gorgeous and not crowded at all.
Best of luck.