well I am ok waking up at 5am, but not my better half!

What did you end up doing?

I have a long layover at NRT during my trip to Asia (Arrive at 8:45am and leaving at 9:00am the next day) and wondering whether I should stay at the hotel in Tokyo or come back to NRT.

Also, anyone know what time the NRT opens? Do you guys think I could skip the hotel and come back to NRT as soon as it opens from Tokyo? Call me crazy, I'm thinking of seeing Tokyo as much as possible within 23 hours (without sleeping) when I'm there. :D Besides, I'm flying Business to SIN (7 hours flight) so guessing I can sleep on the plane. Thanks in advance.

The first Narita Express leaves Tokyo Station at 6:18 am and arrives at NRT at 7:18 am. For a 9:00 am flight in C/J, that ought to be early enough to make it. There is another at 6:30 am, arriving at 7:30 and again at 7:00 am, arriving at 7:56 am, which might be cutting it pretty short.

You can also catch those two earliest N'Ex's at Shinagawa (6:05 am and 6:17 am), Shibuya (6:01 or 6:13 am) or Shinjuku (5:53 and 6:05 am.) They actually start earlier at minor stations but might be tough for a first-timer to find.

Remember public transit pretty much stops operating between the hours of midnight/1am through 5am. So during that period you are essentially stuck in one area of Tokyo, unless you walk or pay for upcharged taxis to get around at those hours.