I came across this the other day. A nice "official" NRT transit guide with a chapter on long layovers and stepping outside of the airport.
I wouldn't base my trip on it but it looked interesting in a glossy tourist guide kind of way.
Main Page.
http://www.narita-airport.jp/en/guid...ook/index.html
Specifically relating to long layovers.
http://www.narita-airport.jp/en/guid...book/15-18.pdf