By plane
From Narita Airport, Takasaki is served by Azalea Limousine Buses operated by Chiba Kotsu; buses leave once every 1 1/2-2 hours 3 hours to/from Takasaki Station, ¥4500. By train, the easiest and most expensive way to reach Maebashi is to take the Narita Express to Tokyo Station, then the Joetsu Shinkansen to Takasaki Approx. 2 1/4 hours, ¥7800, no charge with the Japan Rail Pass or JR East Pass. Reservations for the Narita Express and Shinkansen can all be made from Narita Airport.
From Haneda Airport, Limousine buses operate to/from Takasaki Station 3 hours, ¥3500. Going by train is much faster, but more expensive and requires more transfers: The Keikyu Line to Shinagawa, the Yamanote Line to Tokyo, and the Shinkansen to Takasaki Approx. 1 3/4 hours, ¥5200; cheaper with unreserved shinkansen seat. You can purchase tickets for the JR portion of the journey upon reaching Shinagawa.
By train
Takasaki is a stop on the Joetsu Shinkansen and Nagano Shinkansen lines, and is a hub for the JR Takasaki, Hachiko, Ryomo, Joetsu and Shin-etsu lines.
Frequent Shinkansen services depart Tokyo station for Takasaki every 15-30 minutes, with more frequent departures for the evening rush. You can reach Takasaki in about one hour, at a cost of ¥4800. Regular trains on the Takasaki Line depart from Ueno station 2-3 times per hour, reaching Takasaki in about 2 hours at a cost of ¥1890.
There are also hourly departures for Takasaki on the Shonan-Shinjuku Line which runs via Shinjuku station 1 3/4 - 2 hours, ¥1890 from Shinjuku.
By bus
Nippon Chuo Bus operates several daytime bus services from the Tokyo area to Takasaki. All buses stop at the Hilton Tokyo in Shinjuku, with some buses also stopping in Ikebukuro and Akihabara 2 1/4 hours to/from Shinjuku, ¥1500.
Other long distance buses include the Tokai Liner daytime runs from Shizuoka and Nagoya, Sendai Liner overnight runs from Sendai, and Silk Liner overnight runs from Nara, Kyoto and Osaka. All of these buses are operated by Nippon Chuo Bus.