Northern Kyushu 9 days

Hello all,

I'm slowly planning my trip early next year.

I have my route as such:
Day 1: Fukuoka - Kurokawa (hida bus)
Day 2: Kurokawa - Yufuin - Nagasaki (Kyushu Odan bus - OitaNagasaki bus... is there a faster route?)
Day 3 & 4: Nagasaki
Day 5: Sasebo - Kujukushima day trip
Day 6: Sasebo - Imari - Arita - Saga - Sasebo
Day 7: Ureshino
Day 8 & 9: Fukuoka

I am at a lost as to whether I should be getting the 3 day or 5 day pass. Where do I even start using? Some advice would be much appreciated.

Thank you so much in advance,
Melody