Kyushu 6 days plan

Hi there, please advise if below plan is ok; any other places of interests I should not miss.
Day 1- Nagasaki (Glover, Oura, ChinaTown & Inasa)
Day 2- Nagasaki (Peace Park, Atomic Bomb museum & Huis Ten Borsch)
Day 3- Kumamoto (Suzenji Park & Kumamoto Castle, Mt Aso & Takachiho Gorge)
Day 4 - Beppu(Jigoku, Sand bath & Hello Kitty Land)
Day 5 - Kitakyushu (Space world)
Day 6 - Fukuoka(Dazaifu, Canal City, Tenjin & Yati)

Day 3 is impossible. You need at least two days to cover Kumamoto, Aso and Takachiho and then continue to Beppu. That is when using a rental car. Possible more of traveling by public transportation, because access to Takachiho by public transportation is very infrequent and inconvenient.

Your itinerary looks pretty full already. Here are some random thoughts:

It is doubtful whether you can cover Kumamoto, Mt. Aso and Takachiho Gorge in 1 day, esp. if you have to rely on infrequent public transport.

Beppu is a popular sightseeing destination for the Jigoku Hells, but for an onsen experience, Yufuin and Kurokawa are better.

When going to Harmonyland (Hello Kitty Land), be sure to be there for the outdoor parade at noon.

You may not need a whole day for Space World. See whether you can squeeze in Mojiko after the theme park. Stay in Mojiko after sunset and go up to Mojiko Retro Tower View for a beautiful lit-up evening view of the town. Mojiko is less than an hour's JR from Hakata.

Doubtful whether you still got time but Dazaifu is ideally combined with a visit too to Yanagawa. There is a combine rail ticket to the 2 places from Fukuoka.

Don't think you can get squeeze it in (unless you take time out of Nagasaki) but after HTB, a cruise on the Tsukumojima Islands (99 Islands) for the scenery is worth considering.

Beppu is a popular sightseeing destination for the Jigoku Hells, but for an onsen experience, Yufuin and Kurokawa are better.

For a rural experience, Yufuin and especially Kurokawa are recommended over Beppu. But for pure bathing, Yufuin is simply not on the same level as Beppu and Kurokawa. Some of Japan's best baths are located in Beppu, including some unique mud baths, an amazing roof top bath with views over the entire city and sand baths. Beppu has much more to offer than just the touristy hells.

Hi all, thanks for the great suggestions.

Uji-san, I will be using public transporatation to Takachiho. Is the place worth going? Can you recommend what other places of interest I must see in Beppu, and a good place in Beppu for sand and mud bath?

William5, please advise what else to do in Mojiko and whatis in Yanakawa.

Thanks!

William5, and also advise how can I book the cruise for the Tsukumojima Islands; how long does this cruise takes and what is the cost? Do I need to make reservation?

I will be using public transporatation to Takachiho. Is the place worth going?

It is a nice place, but if you don't have a car, I would seriously think about whether the effort is worth it. Please look in detail at the complicated situation with public transportation in the area.

Can you recommend what other places of interest I must see in Beppu, and a good place in Beppu for sand and mud bath?

Some of the better baths are introduced here:
http://www.japan-guide.com/e/e4701.html

what other places should I see in Beppu?

I can always extend my 6-days to 2 more days..if there are any other MUST SEE places in Kyushu :)

Many of the sites in Mojiko are within walking distance of the JR station. Of interest is the Kyushu Railway History Museum where you can ride a toy-like rail engine, a treat which children will love. Another unique site is the Shimonoseki-Mojiko Tunnel where you can walk from Kyushu back to Honshu. The tunnel is reached by 10-15 min bus from the JR station.
http://www.retro-mojiko.jp/english/index.html

The best way to enjoy Yanakawa is to take a canal punt. Another thing not to be missed there is the popular Unagi eel on steam rice.
http://www.yanagawa-net.com/eng/index.html

Information on "99 islands" cruises:
http://www.pearlsea.jp/english/cruising.html

Sand bath in Beppu:
http://www.hyotan-onsen.com/pdf/english.pdf
Sand and mud baths in Beppu:
http://www.beppu-navi.jp/ml/english/hotspring.htm

Apart from the touristy "hells" in Beppu, make an effort to go for the site shown in the following blog and try out the "hell pudding"
http://www.wretch.cc/blog/bearpalm/14748500
http://www.japan-guide.com/daily/?040419

Kyushu has so much to offer that it is hard to pick for a 6-8 days itinerary. Without rushing too much, your initial idea of concentrating on the northern region is a good idea. Save the south for a future trip.

Without going further south from Takachiho Gorge, sites worth considering in the north IF you still have time are: Kokura, tea plantations in Yame area, Usa Jingu, Usuki Sekibutsu Stone Buddhas, African Safari Park, Kokonoe Yume Otsurihashi suspension bridge, Aso Refresh Resort and Genki Forest, Mitsui Greenland Park and Ultraman Land, Tsujunkyo Aqueduct/Bridge, Cuddly Dominion Zoo, Shimabara, Unzen, Sasebo, Arita, Imari, Karatsu, Yobuko, Ureshino Onsen, Saga, Yutoku Inari Shrine, Yoshinogari Historical Park, Tosu Premium Outlet, etc.
The list is long and it is far from exhausted. You have to choose according to your interest and available time. Depending when you are going, there are flower parks and u-pick fruit farms that are opened for visit if the season is right. Also there are seasonal events and festivals that are worth going for if they coincide with the time of visit.

Where n how to get the the combined rail ticket for dazaifu n yanagawa? How much it cost?

For the 8 days plan, should I get Kyushu railway pass or sunq pass or both?

Combined ticket for Daizaifu and Yanagawa is 2800 yen from Fukuoka Nishitetsu station in Tenjin.

http://www.nishitetsu.co.jp/train/ticket/i_dazayana.htm