Tokyo Narita airport opened up it’s terminal 3 earlier this year for some of the low cost carriers like the Jetstar airline. If you are arriving into Terminal 3 then you may need to make your way to the bus stops or the train line at terminal 2. There is a bus transfer however you will probably find the walk is just as easy. Facilities at the terminal are quite good with plenty of restaurants and a Lawsons convenience store. There is also a 7/11 cash machine which you can use with your Visa or Mastercard to get some yen. (probably better to get some before you leave home though). It is a 520 meter covered walkway between terminals on a running track surface which is quite easy going. It is covered but will be really cold in the winter so have a jacket handy and some gloves.