Do I need a 7 day pass?

Hi there!

Economically, I think it'll be better to purchase individual JR tickets if this is your only travel. Lets take a look at the costs:

1. Narita airport terminal 1 > Tokyo: ¥3140, (62mins, 79km)
2. Tokyo > Kobe(hyogo): ¥14270, (229mins, 589km)
3. Kobe(hyogo) > Kyoto: ¥1050, (57mins, 75km)
4. Kyoto > Kansai airport: ¥3690, (79mins, 99km)

JR ticket cost: ¥22150 for 4 legs

As a 7 day pass is ¥28,300, you'll need to spend another ¥6150 on JR tickets for a rail pass to be economical. You could easily make this up, for example with a day trip to Nikko, travel around Tokyo, or a day trip to Hiroshima from Kyoto, but it very much depends on your travel plans.

Hope this helps!