[About train in Tokyo]
Center of Tokyo has mainly 3 railway companies. JR (Japan Rail) and two subways (Tokyo Metro & Toei, total 13 lines).
JR Yamanote line Is the most useful one. Go through big towns like Shinjuku, Shibuya, Ikebukuro.If you say “metro” in Tokyo, it means the subway “Tokyo Metro”. not JR trains.
[About Takadanobaba station]
Takadanobaba station is linking the JR Yamanote line and metro Tozai line, and this two line is connected at Waseda exit. Other exits (like JR Toyama exit or metro exit #6, exit #7) are not able to transfer to another line. Also there is Seibu line but I guess most tourists never use this one.
English map of Takadanobaba station
[From Narita to Takadanobaba]
You can use a bus or train.If you have a valid JR rail pass, you should take JR NEX.if not, other ways are cheaper and faster.
[JR TRAIN]
If you have a non-Japanese passport, you can take a train named NEX (JR Narita express), round ticket with 4070yen. But if you buy only one way, 3,250yen.
(If you have a valid Japan Rail Pass, NEX is included in the price.)
Narita airport –(Narita express 90min)-> Shinjuku station –(JR Yamanote line 5min)-> Takadanobaba
[Keisei TRAIN]
The fastest way from Narita to Tokyo is taking Keisei Skyliner, 2570yen/one way.
Change to JR Yamanote line at Nippori station, 170yen to Takadanobaba.
Narita airport –(Keisei Skyliner 40min)-> Nippori station –(JR Yamanote line 17min)-> Takadanobaba
[BUS]
The cheapest way is by bus, you can take the Airport Bus TYO-NRT for 1300yen. (It was called “Tokyo shuttle” before.)
Narita airport –(Airport bus TKO-NRT 65min)-> Tokyo station –(walk 2min)-> Nihombashi station –(metro Tozai line 15min)-> Takadanobaba
[Bus ticket counter, and bus stop at Narita airport]
Buy a ticket at the Keisei Bus counter (See the map below). A bus comes every 20 min.
(There is another bus named “Access Narita”, which leaves from the same bus stop.You can buy this bus ticket directly from the bus driver, but it arrives in a different bus stop of Tokyo station.Tokyo shuttle bus is easier if you head to Takadanobaba.)
[Map of Tokyo station bus stop.]
From Tokyo station bus stop, walk to the Metro Tozai line Nihombashi station exit A3. It's about 7 ~ 8 minutes from the bus stop. If you want to use an elevator, enter the building behind the exit. It's connected to the station underground.
If you don't want to use steps at all, walk to Yaesu north exit of Tokyo station, then take JR Yamanote line. Takadanobaba is about 30 min in the Ueno & Ikebukuro direction. (JR Tokyo station is huge and bit complicated.)
English 
Japanese
How far is terminal 1 from terminal 2 and must we take bus or can walk over.
Are the terminal 1 and 2 connected.
There is an airport shuttle bus between terminal 1 and 2, it takes about 10 minutes.
You also can take the train but you'll need to pay.
From terminal 2 to terminal 3, you can walk (about 15 minutes.)