Access To the Fuji Five Lakes
You have to transfer to Fujikyu Railway Line from JR Chuo Line At Otsuki station to reach Kawaguchiko station.
There are some JR direct trains which you do not have to transfer at Otsuki station. See here.
All these train's final destination is Kawaguchiko Station. You can get off at stations like Fujisan or Fujikyu Highland, too.
There are lots of highway buses operated between Fuji Five Lakes area and Metropolitan area.
The highway buses start at one of following locations in Tokyo or Narita.
(1) Tokyo Station Yaesu Bus Terminal
(2) Shinjuku Bus Terminal
(3) Shibuya Bus Terminal
(4) Haneda airport
(5) Narita airport
You can see the detail here.
Within the Five Lakes area, local Sightseeing Buses are available. You can find them at Kawaguchiko Station Bus Terminal.
There are 5 routes as following.
(1) Kawaguchiko Sight Seeing Bus(Red Line)
(2) Saiko Sightseeing Bus(Green Line)
(3) Narusawa/Shojiko/Motosuko Sightseeing Bus(Blue Line)
(4) Fujiyoshida/Oshino/Yamanakako Sightseeing Bus(F-Line)
(5) Mount Fuji World Heritage Loop Bus
You can see the detail at Fujikyu homage here.
Chuo Express Way Route
(This route is shorter than others)
(1) Take Metropolitan Highway Rout 4 or take Chuo Express Way directly.
(2) Go straight to Chuo Express Way.
(3) Take Kawaguchiko Line At Otsuki(Left).
(4) Exit At Kawaguchiko IC. If you want to go to Lake Yamanaka or Oshino, exit at Yamanakako IC.
Tomei Express Way Rout
(1)Take Tomei Express Way at Tokyo IC or go through from Metropolitan Highway Rout 3 from Shibuya to Tomei Express Way.
(2) Exit At Gotemba IC.
(3) Take R138 to North.
(4) Take Higashi-Fujigoko-Doro(East Fuji-Five-Lakes road) at Subashiri IC.
(5) Exit at Fujiyoshida IC(You can not exit at Kawaguchiko IC) . You can exit at Yamanakako IC to go to Lake Yamanaka or Oshino.