It takes about one hour and 40 minutes to Tsukuba Center. (The bus, without going through Japanese Expressways, is hardly caught in a traffic jam and thereby the schedule would be reliable.) There are six bus stops: ''Shin-Tone-Machi'', ''Ryu-Ga-Saki New Town'', ''Ushiku'', ''Hitachino-Ushiku Station'' (some of these are skipped occasionally), ''Tsukuba Center'' and ''Tsuchiura Station''; you should get off the bus at Tsukuba Center (not Tsuchiura Station).
Tsukuba (or ''Tsukuba Science City'') is located about 60km north of Tokyo and about 40km northwest of the Narita International Airport. Tsukuba Center and Epochal, within a walking distance each other, are in the central area of Tsukuba and about 10km south of KEK.
The easiest way is to take a direct bus service, called Airport Liner ''NATT'S'', from the Narita Airport through Tsukuba Center to Tsuchiura Station. Tickets are available at the ''Airport Limousine Keisei'' counter on the 1st floor in the arrival lobby, and the fare is 2,540 yen per person. (Note that the ''Airport Limousine Bus'' counter on the same floor, operated by another company, does not take care of the NATT'S bus service.) The bus stop is located right outside of the terminal, and the bus leaves the Airport at 07:40, 09:05, 10:35, 12:50, 14:30, 16:15, 17:20, 18:45, and 20:10.
In case your flight is not compatible with the bus schedule (leaving the Airport at 20:10 in the last), then you have to go to the Tokyo area at first by the JR line, Keisei line or Airport Limousine Bus (about two hours, 2,000-3,000 yen). The transportation from Narita to Tsukuba by taxi will cost as much as 20,000 yen.
Take the JR Yamanote line to Akihabara station, where you will change for the Tsukuba Express ‘TX’. The entrance to the TX is located at the east side exit of the Akihabara station. It takes about 10 minutes from JR to the TX ticket gate on foot.
At TX Akihabara station, buy a ticket to Tsukuba station (1,150 yen per person) and take a Rapid train (45 minutes) or a Semi-Rapid train (52 minutes); a limited number of Local trains reach Tsukuba station (57 minutes). Take the exit A4 or A3 of Tsukuba station to the Tsukuba Center bus terminal.
TX trains leave the stations every 15 minutes; the first and last trains leave the TX Akihabara station for Tsukuba station at 05:30AM and 23:30, respectively, and the first and last trains leave Tsukuba for Akihabara at 05:07AM and 23:14, respectively. You can enjoy a short trip from Tsukuba to Tokyo easily by using the TX trains.