Getting around Narita is pretty easy. Airport buses run often between terminals (I think there are only two). The wife and I killed some time there several years ago waiting for a connection to Fukuoka, and we spent part of the time visiting the other terminal. BTW, the eating situation at Japanese airports is GREAT. Many restaurants, great food, comfortable, friendly service, no rip-off prices.
Everything you need to know here:
NARITA INTERNATIONAL AIRPORT OFFICIAL WEBSITE
Check out the Airport Guide/Facilities and Services/Relax While Waiting/Dayrooms and Showers section. Has all the info you need. You can even reserve your dayroom online.