6 hours in Narita: Exit-Re-entry time

I have a 6 hour layover in Narita between international flights. I want to go into Narita or other nearby villages. How hard is it to clear Customs/Immigration and then come back and get back into American for my flight home?

You can ask for a 72-hour shore pass application from your airline counter when you check in before your flight to Narita. A person at your airline counter will look at your tickets and write an application for you to take to the immigration officer in Narita. It basically has your name and flight details on it, signed by an airline official (the counter person).

Head to immigration after landing in Tokyo and get in line. When you get to the immigration window, you give the officer the application. He'll ask why you want to leave the airport and all you have to say is that you want to look around the temple in Narita during your 6-hour layover. He will put a 72-hour Shore Pass in your passport.

You should leave plenty of time to go through immigration and to get back through security. Sometimes both can be backed up and it can take forever. Other times, though, can be empty and you walk right through.

Some airlines have been known not to issue a Shore Pass application (they probably don't know about it.) I don't know if they still do it, but once I was able to get the shore pass issued at immigration. I would check one of the info places at immigration before the official windows if you want to try this.

I have a 6 hour layover in Narita between international flights. I want to go into Narita or other nearby villages. How hard is it to clear Customs/Immigration and then come back and get back into American for my flight home?

Not hard at all, however, note that a 6 hour layover leaves you very little time for sightseeing. Adding together time for immigration, travel, and then check-in/security time leaves you with only around 1-2 hours to see the sights.

I suggest checking out this page for more info on what to do in Narita. Likely you will only have time to see one thing:

http://www.japan-guide.com/e/e6400.html

Also, not sure about the 72 hour pass mentioned above, but depending on your citizenship you may qualify for an automatic tourist visa. That would save you time getting through immigration.