Kyushu is home to dialects of Japanese that are almost incomprehensible to speakers of standard Japanese -so much so that it was utilised during World War 2 for preventing interception by the Allies of Japanese communications. Even native speakers of Japanese from Honshu often have problems understanding the conversations of locals. However, all people are able to speak standard Japanese and especially in the cities younger people may also have a limited command of English.
Fukuoka is Japan's busiest international hub after the trio of Tokyo, Chubu and Kansai and has excellent connections throughout Asia and Japan. All the other prefectural capitals also offer limited service within Japan and to a few major Asian cities (typically Seoul and Shanghai).
The San'yo Shinkansen line runs from Osaka to Fukuoka and many trains continue along the Kyushu Shinkansen line to Kagoshima. All Shinkensen trains stop at Kokura Station in Kitakyushu and Hakata Station in Fukuoka; a trip by train all the way from Tokyo takes 5:40 by Nozomi and costs ¥22,000. There are no Hikari trains that go the full distance from Tokyo to Hakata, so With the JR Pass, you'll need to change trains. You can also go from Osaka to Hakata with the JR West San'yo Pass.
The Kyushu Shinkansen crosses the west side of the island to Kagoshima in the south. Many trains to Kagoshima start in Osaka, and the full course takes about 4 hours by Mizuho and ¥21,000. The JR pass is not accepted on Mizuho trains, but they are accepted on Sakura trains which make the journey in 4.5 hours. A journey from Tokyo (with a change in Osaka) takes a little over 7 hours and costs just under ¥30,000, add an hour with the JR Pass for a Hakari to Sakura connection in Shin-Osaka or Okayama.
The Hakata to Kagoshima run takes about 1.5 hours. There are also good Limited Express trains servicing most anywhere of interest on the island, so you can take train from Hakata to just about anywhere else of interest on the island in about an hour in a half. The exception being Miyazaki which is about four hours from hakata.
Willer Express  is a company which provides daily night time bus services from Nagoya, Tokyo, and Osaka to Kyushu. They offer an online booking services in Japanese, English & Korean.
The train is the transport mode of choice on Kyushu. The Kyushu Shinkansen zips across from Fukuoka (Hakata) via Kumamoto to Kagoshima in 1:20, and there is fairly rapid limit express network to get anywhere else. There are also some scenic local train lines such as the JR Hisatsu Line (肥薩線) from Kumamoto via Yatsushiro to Kagoshima is considered one of the most scenic in Japan, and there are comfortable, sightseeing oriented, trains on these lines, and there are some runs with unique roll stock, most notably the Aso Boy from Kumamoto to Mt. Aso and the Steam Locomotive Hitoyoshi from Kumamoto to Hitoyoshi, along the Hisatsu Line.
The Kyushu Rail Pass , available only for those not residing in Japan (foreigners with a "temporary visitor" status or Japanese citizens with permanent residence overseas), offers unlimited travel on JR Kyushu's lines, including the Kyushu Shinkansen but not the San'yo Shinkansen between Hakata or Kokura, nor any JR Kyushu buses. Unlike the regular full JR Rail Pass, the JR Kyushu Rail Pass may be purchased after arriving in Japan but only if you are in Japan with a "temporary visitor" status. There are two types of Kyushu Rail Pass: one for the Northern Kyushu Area (all JR lines including and north of the Hohi Main Line between Kumammoto City and Oita City), and the full pass which covers the entire island. Multiple purchases of the passes are allowed as long as the times do no overlap.
The prices of the pass are as follows:
Northern Kyushu Area 3-day pass ￥8,500 5-day pass ￥10,000
All Kyushu Area 3-day pass ￥15,000 5-day pass ￥18,000
One JR pass, the San'yo-Shikoku-Kyushu Pass , is available in two versions like the Kyushu Rail Pass but also includes the bullet trains and main line west of Osaka, and all JR trains in Shikoku. The version covering northern Kyushu costs ¥22640 for 5 consecutive days, and the version covering all of Kyushu costs ¥25720 for the same period. With this pass you CAN use Mizuho trains between Osaka and Kumamoto/Kagoshima respectively, as well as Nozomi trains between Osaka and Hakata. A round-trip between Osaka and Kyushu by bullet train (approx. ¥30000 to Hakata) will be cheaper if this pass is purchased. The sale of this pass will be discontinued after March 31, 2015, and any vouchers for the pass can be exchanged into a pass until June 30, 2015.
Buses serve those parts of Kyushu outside the railway network, but schedules tend to be very limited. There is also a highway bus system paralleling the train network, which you can use through the Raku Bus  website. They also offer SUNQ 3-4 day unlimited travel passes: 4-day All Kyushu Pass ¥14,000; 3-day All Kyushu Pass ¥10,000; 3-day Northern Kyushu Pass ¥8,000.
There are some great hikes around Kyushu called Olle Hiking. The lenght varies between 10 to 15 km as well as the difficulty. Visit their website for more details and locations. 
Kyushu is the home of shōchū (焼酎), the fiery Japanese distilled liquor. It's typically around 25%, but some varieties can be much stronger. It can be distilled from nearly anything including rice, barley, brown sugar and buckwheat, but Kyushu is best known for potato shōchū (芋焼酎 imojōchū), particularly that from the ancient province of Satsuma (modern-day Kagoshima). See also "Japanese sake tourism#Shochu and Awamori distilleries" article.
Chugoku - The Chugoku region offers many great experiences for travellers, such as Hiroshima, the first city to experience an atomic bombing, Okayama, home to one of Japan's Three Famous Gardens, Izumo, with the second holiest Shinto Shrine in Japan, and Tottori, with Japan's only sand dunes.