Narita is a l-o-n-g way from Tokyo so if your flight out departs before, say, 11am you'll find it a lot easier to stay your last night at the airport. The Hilton is also, I believe, a decent option here. The HI has a good wing and a bad wing according to reviews - I got the good wing when I stayed there probably due to my status. It's hardly life changing but it is also well under $75 a night, so you might even prefer cash to points.

It is pretty much impossible to base yourself at Narita for your entire trip due to the distance from downtown Tokyo - even the 'express' train is a fair journey.